JP6957854B2 - Molded product and manufacturing method of molded product - Google Patents

Description

The present invention relates to a molded product and a method for producing the molded product.

Fiber reinforced plastic molded bodies molded from non-woven fabrics containing reinforced fibers such as carbon fiber and glass fiber (also called fiber reinforced plastic molded sheet) have already been used in various fields such as sports, leisure goods, aircraft materials, and electronic equipment members. It is used in the field. Thermosetting resins and thermoplastic resins are used as the resin that serves as a matrix in the fiber-reinforced plastic molded body. In recent years, the development of fiber-reinforced plastic molded bodies using the thermoplastic resin has been promoted.

In recent years, it has also been proposed to use natural fibers as reinforcing fibers. For example, Patent Document 1 describes fiber molding containing pulp fiber and a hydrophilic polymer as main components, having surface pores having a pore diameter of 0.5 to 5 mm, and having a density of 0.05 to 0.20 g / cm ^3. The body is disclosed. Here, the fiber-molded body is used for cultivating plants by stabbing cut flowers and the like, and it is studied to improve the water retention and disposability required for plant cultivation.

Japanese Unexamined Patent Publication No. 2004-277978

However, the molded product described in Patent Document 1 exhibits morphological stability for plant cultivation, but has weak compressive strength for use in other containers, and has sufficient strength particularly in a dry state. There is a problem that it is not done.
Further, even a molded product having sufficient compressive strength in a dry state may be required to be easily disposed of. For example, it can be said that a molded product having a predetermined shape and having sufficient strength in a dry state, but which is easily compressed and deformed by being immersed in water, is excellent in ease of disposal.

Therefore, the present inventors have proceeded with studies for the purpose of providing a molded product that has sufficient strength in a dry state but can be easily compressed and deformed in a wet state.

As a result of diligent studies to solve the above problems, the present inventors set the density of the molded product within a predetermined range in the molded product containing the hydrophilic material and the thermoplastic resin to dry the molded product. It has been found that although it has sufficient strength in the state, a molded product that is easily compression-deformed by being immersed in water can be obtained.
Specifically, the present invention has the following configuration.

[1] A molded product containing a hydrophilic material and a thermoplastic resin, wherein the density of the molded product ^{is greater than 0.10 g / cm 3 and} 1.00 g / cm ³ or less, and the molded product is dry. When the compressive strength of the molded product is P and the compressive strength of the molded product when wet is Q, the compressive strength reduction rate (%) calculated by the following formula (1) is 10% or more. ..
Decrease rate (%) = (1-Q / P) x 100 formula (1)
[2] The molded product according to [1], wherein the hydrophilic material is pulp fiber.
[3] The molded product according to [1] or [2], wherein the thermoplastic resin has a melting point of 200 ° C. or lower.
[4] The molded product according to [2] or [3], which comprises a fiber-containing plastic region containing pulp fibers and a thermoplastic resin, and a resin region in contact with at least one surface side of the fiber-containing plastic region. ..
[5] The molded product according to [4], wherein the content of the pulp fiber is 40% by mass or more with respect to the total mass of the content of the pulp fiber and the thermoplastic resin.
[6] The molded product according to [4] or [5], wherein the resin region contains a resin having a melting point of 200 ° C. or lower.
[7] The molding according to any one of [1] to [6], wherein the thermoplastic resin is at least one selected from polylactic acid, polybutylene succinate, ethylene vinyl alcohol copolymer, polyethylene terephthalate and polyolefin. body.
[8] A method for producing a molded product, which comprises a step of molding a sheet for a molded product containing a hydrophilic material and a thermoplastic resin, wherein the molding step is selected from a vacuum molding step and a pressure molding step. step is a step density is formed largely 1.00 g / cm ³ or less of the molding than 0.20 g / cm ^3, compressive strength of the dry shaped bodies are to include at least one step is, molding A method for producing a molded product, wherein the compression strength reduction rate (%) calculated by the following formula (1) is 10% or more, where P is P and the compression strength of the molded product when wet is Q.
Decrease rate (%) = (1-Q / P) x 100 formula (1)
[9] The hydrophilic material is pulp fiber, and in the molding step, the pulp fiber, the fiber-containing plastic molded product sheet containing the thermoplastic resin, and the resin sheet are laminated, and the resin sheet-containing molded product is used. The method for producing a molded product according to [8], which comprises a step of obtaining a sheet and a step of molding a resin sheet-containing molded product sheet by at least one step selected from a vacuum molding step and a pressure molding step. ..

According to the present invention, it is possible to obtain a molded product which has sufficient strength in a dry state but can be easily compressed and deformed by being immersed in water. The molded product of the present invention has a high degree of freedom in shape change in a wet state and is excellent in compressibility at the time of disposal, so that it is easy to dispose of. In addition, it is possible to reduce the risk of injuring the human body at the corners and ends of the molded product during disposal and handling in a wet state.

FIG. 1 is a schematic cross-sectional view illustrating an example of the layer structure of the molded product of the present invention.

Hereinafter, the present invention will be described in detail. The description of the constituent elements described below may be based on typical embodiments or specific examples, but the present invention is not limited to such embodiments.

(Molded body)
The present invention relates to a molded product containing a hydrophilic material and a thermoplastic resin. Here, the density of the compact is increased 1.00 g / cm ³ or less than 0.10 g / cm ^3. Further, when the compressive strength of the molded product when dry is P and the compressive strength of the molded product when wet is Q, the compressive strength reduction rate (%) calculated by the following formula (1) is It is 10% or more.
Decrease rate (%) = (1-Q / P) x 100 formula (1)

Since the molded product of the present invention has the above-mentioned structure, it has sufficient strength in a dry state, but can be easily compressed and deformed by being immersed in water. That is, the molded product of the present invention has a high degree of freedom in shape change in a wet state and is excellent in compressibility at the time of disposal, so that it is easy to dispose of.

The density of the molded product of the present invention may be larger than ^{0.10 g / cm 3 , preferably 0.20 g / cm 3} or more, and more preferably 0.25 g / cm ³ or more. The density of the molded product of the present invention ^{may be 1.00 g / cm 3} or less, preferably 0.80 g / cm ³ or less, and ^{more preferably 0.70 g / cm 3} or less. It is more preferably 0.60 g / cm ^{3 or less.} By setting the density of the molded product within the above range, sufficient strength can be exhibited in the dry state, and the degree of freedom in changing the shape in the wet state can be increased.

The compressive strength reduction rate (%) of the molded product of the present invention may be 10% or more, preferably 15% or more, more preferably 20% or more, and further preferably 25% or more. It is preferably 30% or more, more preferably 35% or more, and particularly preferably 35% or more. The compressive strength reduction rate (%) may be 99.9%.

The compressive strength of the molded product of the present invention in a dry state (hereinafter, also referred to as dry compressive strength) is preferably 0.1 kN / m or more, more preferably 0.5 kN / m or more. It is more preferably 0.7 kN / m or more, and particularly preferably 0.8 kN / m or more. The upper limit of the dry compressive strength is not particularly limited, but can be, for example, 5.0 kN / m.

Further, the compressive strength of the molded product of the present invention in a wet state (hereinafter, also referred to as wet compressive strength) is preferably 0.9 kN / m or less, and more preferably 0.8 kN / m or less. It is preferably 0.7 kN / m or less, and more preferably 0.7 kN / m or less. The lower limit of the compressive strength when wet is not particularly limited, but may be 0.01 kN / m.

Here, the compressive strength in the dry state and the wet state can be measured according to the paper and paperboard-compressive strength test method (ring crush method) of JIS P 8126. Specifically, the molded product is cut into 12.7 mm × 152.4 mm and used as a measurement sample. This measurement sample was left at 23 ° C. and 50% relative humidity for 24 hours to prepare a sample in a dry state, and was compressed according to the JIS P 8126 paper and paperboard-compressive strength test method (ring crush method). Measure strength.
For the compressive strength in the wet state, JIS P 8126 paper and paperboard-compressive strength test method (ring crush) was obtained by immersing the entire area of the measurement sample cut out to 12.7 mm × 152.4 mm in water for 1 minute. Measure according to the method). In the present specification, a sample obtained by immersing all the regions of a sample cut into 12.7 mm × 152.4 mm in water for 1 minute is used as a wet molded product sample.
Then, the rate of decrease in compressive strength (%) can be calculated by the following formula.
Decrease rate (%) = (1-Compressive strength when wet / Compressive strength when dry) x 100

In the molded product of the present invention, the molded product can be brought into a wet state not only by immersing all the regions in water but also by immersing only the end region of the molded product in water. This is because the molded product of the present invention contains a hydrophilic material, so that water can be absorbed from the end face of the molded product end region. Since the molded body of the present invention contains a hydrophilic material and the density of the molded body is within the above-mentioned range, the molded body is characterized in that it has high water absorption and high water absorption. Specifically, the water absorption of the molded product of the present invention can be measured according to the paper and paperboard-water absorption test method (Krem method) of JIS P 8141. For the water absorption from the end face, a measurement sample laminating with polyethylene resin (PE) was cut out to a size of 15 mm × 200 mm so as to prevent water absorption from the surface, and a region of 15 mm from one end in the longitudinal direction of the sample was immersed in water. The height (mm) of water rising is measured by hanging the sample in 10 minutes. In the present invention, the height (mm) of water rising from the edge is preferably 10 mm or more, more preferably 20 mm or more, further preferably 30 mm or more, and the maximum length of the sample. Is most preferable.

FIG. 1 is a schematic cross-sectional view illustrating an example of the layer structure of the molded product of the present invention. As shown in FIG. 1A, the molded product 10 of the present invention includes a hydrophilic material-containing region 12. The molded body 10 may consist of a hydrophilic material-containing region 12. Further, as shown in FIG. 1 (b), the molded product 10 of the present invention may include a hydrophilic material-containing region 12 and a resin region 14. The resin region 14 functions to increase the strength of the molded product 10.

note that. In the present invention, the hydrophilic material-containing region 12 is preferably a hydrophilic material-containing layer, and the resin region 14 is preferably a resin layer. That is, it is preferable that the molded product of the present invention contains a hydrophilic material-containing layer and a resin layer, and the resin layer is arranged so as to be in contact with at least one surface side of the hydrophilic material-containing layer.

As shown in FIG. 1B, when the molded product 10 has the resin region 14, the resin region 14 may be provided on both sides of the hydrophilic material-containing region 12. In this case, the resin region 14 can not only increase the strength of the molded product 10, but also increase the water resistance of the surface of the molded product 10. Further, by providing the resin regions 14 on both surfaces of the molded body 10, the smoothness and glossiness of the surfaces can be enhanced, and the designability can be improved.
In the present invention, even when the resin region 14 is provided, at least one side end surface of the molded product 10 is not covered with the resin region 14. That is, a part of the hydrophilic material-containing region 12 is exposed on at least one side end surface of the molded product 10. Therefore, when the molded product 10 of the present invention is immersed in water, water can be absorbed from the side end faces, and the rate of decrease in compressive strength can be increased. By providing the resin region 14 in this way, it is possible to improve the water resistance of the surface of the molded body 10 and the compressive deformability at the time of disposal.

As shown in FIG. 1B, it is preferable that the hydrophilic material-containing region 12 and the resin region 14 are laminated in contact with each other. Here, the state in which each region is in contact means a state in which no other layer exists between the hydrophilic material-containing region 12 and the resin region 14. However, in the present invention, the state in which each region is in contact includes a state in which an adhesive layer for adhering both regions is interposed between the hydrophilic material-containing region 12 and the resin region 14.

When the molded product 10 of the present invention has the resin region 14, it can be obtained by laminating the sheet constituting the hydrophilic material-containing region 12 and the sheet constituting the resin region 14 and then undergoing a molding step. In the present invention, in such a molding step, it is preferable that the hydrophilic material-containing region 12 is molded and at the same time, the hydrophilic material-containing region 12 and the resin region 14 are joined. When the adhesive layer does not intervene between the hydrophilic material-containing region 12 and the resin region 14, a part of the thermoplastic resin contained in the hydrophilic material-containing region 12 and a part of the resin contained in the resin region 14 are melted. The hydrophilic material-containing region 12 and the resin region 14 are bonded to each other. Further, when the adhesive layer is interposed between the hydrophilic material-containing region 12 and the resin region 14, a stronger bond is formed in the molding step.

When the molded product 10 of the present invention has the resin region 14, there may not be a linear boundary surface between the hydrophilic material-containing region 12 and the resin region 14. Therefore, between the hydrophilic material-containing region 12 and the resin region 14, there is a boundary region in which a part of the constituent components of the hydrophilic material-containing region 12 and a part of the constituent components of the resin region 14 are mixed. It can also be said that it is. When the adhesive layer is interposed between the hydrophilic material-containing region 12 and the resin region 14, a linear boundary surface may exist between the hydrophilic material-containing region 12 and the resin region 14.

In the present specification, when the hydrophilic material-containing region contains pulp fibers as described later, the hydrophilic material-containing region can also be referred to as a fiber-containing plastic region. In this case, the fiber-containing plastic region comprises pulp fibers and a thermoplastic resin. When the molded body 10 has the resin region 14, the resin region 14 is preferably provided so as to be in contact with at least one surface side of the fiber-containing plastic region.

The thickness of the molded product of the present invention is not particularly limited, but is preferably 0.05 mm or more and 50 mm or less. By setting the thickness of the molded product of the present invention within the above range, it is possible to obtain a molded product that has sufficient strength in a dry state but is easily compressed and deformed by being immersed in water.

The molded product of the present invention is also characterized in that its surface texture is excellent. Specifically, after molding the molded product of the present invention, it is preferable that the surface of the molded product is not transparent or torn. It is preferable that the surface of the molded body is not torn, and when see-through occurs, the area of the see-through portion is preferably 10% or less of the total area of the molded body, and more preferably 5% or less. It is preferably 1% or less, and more preferably 1% or less.

A lid material may be provided on the molded product of the present invention, if necessary. When the lid material is provided, a material having a heat-sealing property may be used for the lid material, or a pressure-sensitive adhesive or a resin may be applied to the lid material so that the lid material and the main body of the molded product can be adhered to each other. Further, a heat seal layer may be provided on the surface of the molded body so that the lid material and the molded body body can be adhered to each other. Alternatively, the lid material and the main body of the molded product may be adhered to each other by containing a thermoplastic resin on the surface of the molded product. When the resin region of the molded body contains a thermoplastic resin, the blending amount of the thermoplastic resin is preferably 10% by mass or more, preferably 20% by mass or more, based on the total mass of the resin region or the fiber-containing plastic region of the molded body. More preferably, 30% by mass or more is further preferable, and 40% by mass or more is most preferable. By changing the blending amount and type of the thermoplastic resin, it is possible to arbitrarily adjust the adhesive strength of the lid material.

Even when the lid material is provided, the compressive strength of the molded product of the present invention is preferably within the above-mentioned range. For example, it is preferable that the compressive strength of the molded product with a lid material in which the lid material is bonded to the entire surface of the molded product described above is also within the above range.

(Hydrophilic material-containing area)
The hydrophilic material-containing region includes a hydrophilic material and a thermoplastic resin.

<Hydrophilic material>

The hydrophilic material in the hydrophilic material-containing region is preferably a fiber derived from an organic resource. Examples of fibers derived from organic resources include pulp fibers, cotton, kenaf, bamboo, hemp, silk, wool and the like. The hydrophilic material-containing region may contain components other than fibers derived from organic resources, and may contain, for example, powders derived from organic resources such as wood flour, glass fibers, ceramic fibers, carbon fibers and the like. good. In addition, in this specification, a hydrophilic material does not include a hydrophilic thermoplastic resin.

Above all, the hydrophilic material is preferably pulp fiber. The production method and type of pulp constituting the pulp fiber are not particularly limited. For example, chemical pulp such as hardwood and coniferous kraft pulp (KP), mechanical pulp such as SGP, RGP, BCTMP and CTMP, waste paper pulp such as deinked pulp, and kenaf, jute, bagasse, bamboo, straw, hemp. Non-wood pulp such as. Further, as the pulp, chlorine-free pulp such as ECF pulp and TCF pulp can be used.

The freeness of pulp fibers is preferably 800 ml or less, preferably 700 ml or less, according to JIS P 811-2: 2 pulp-water freshness test method-Part 2: Canadian standard freeness specified by the Canadian standard freeness method. It is more preferably less than or equal to, more preferably 600 ml or less, and particularly preferably 500 ml or less. Further, the filtrate degree of the pulp fiber is preferably 300 ml or more. By setting the water solubility of the pulp fiber within the above range, the thermoplastic resin can be satisfactorily held during molding, and the molten resin can be prevented from flowing out.

The mass average fiber length of the pulp fiber is preferably 0.1 mm or more and 15 mm or less, more preferably 0.5 mm or more and 10 mm or less, and further preferably 1 mm or more and 5 mm or less. By setting the fiber length of the pulp fiber within the above range, it is possible to prevent the pulp fiber from falling off from the hydrophilic material-containing region when molding the molded body, and to obtain a molded body having excellent strength. It becomes possible to form. Further, by setting the fiber length of the pulp fiber within the above range, the dispersibility of the pulp fiber can be improved. In this specification, the mass average fiber length is an average value of fiber lengths measured for 100 fibers.

The hydrophilic material may contain at least one of a saccharide, a water-soluble polymer, gelatin, and starch.

The above-mentioned saccharides used in the present invention are not particularly limited. For example, monosaccharides include glucose, fructose, galactose, disaccharides include sucrose, malt sugar, lactose, cerbiose, polysaccharides such as amylose and cellulose. Trehalose, water candy, warm sugar, brown sugar, sugar alcohols such as sorbitol, martitol, xylitol, reduced candy, and oligosaccharides include xylooligosaccharides, fructo-oligosaccharides, galactooligosaccharides, milk fruit oligosaccharides, soybean oligosaccharides, and other palatinoses. Can be mentioned.
Examples of the water-soluble polymer include polyacrylic acid and its salt, methacrylic acid and its salt, polyacrylic acid methacrylic acid copolymer, polyethylene glycol, carboxymethyl cellulose, polyvinyl alcohol, polyvinyl pyrrolidone, carbopole, crystalline cellulose, and cellulose. Examples thereof include alginates such as purulan, casein, pectin, starch and sodium alginate, locust bean gum, carrageenan, agar, arabic gum, xanthan gum, hyaluronic acid and its salts, and glucosamine.
As the gelatin, collagen and collagen peptide, gelatin, collagen or collagen peptide derived from cattle, pigs and fish are used, respectively.
Examples of the starch include potato starch, sweet potato starch, tapioca starch, rice starch, corn starch, wheat starch, and barley starch.

The content of the hydrophilic material in the hydrophilic material-containing region is preferably 5% by mass or more, more preferably 10% by mass or more, and 25% by mass or more, based on the total mass of the hydrophilic material-containing region. It is more preferably 35% by mass or more, further preferably 40% by mass or more, particularly preferably 50% by mass or more, and most preferably 51% by mass or more. .. The content of the hydrophilic material is preferably 95% by mass or less. By setting the content of the hydrophilic material within the above range, the rate of decrease in compressive strength can be increased, and the ease of disposal can be improved.

<Thermoplastic resin>
The melting point of the thermoplastic resin is preferably 200 ° C. or lower. The melting point of the thermoplastic resin is more preferably 195 ° C. or lower, and more preferably 180 ° C. or lower. The melting point of the thermoplastic resin is preferably 80 ° C. or higher, more preferably 90 ° C. or higher, and even more preferably 100 ° C. or higher. By setting the melting point of the thermoplastic resin within the above range, deterioration of the hydrophilic material used in combination can be suppressed, and the water resistance and strength of the molded product can be improved.

Examples of the thermoplastic resin that can be used in the present invention include polyesters such as polyolefin resins, polystyrenes, and polyethylene terephthalates (eg, amorphous PET, low melting point PET), acrylonitrile-styrene copolymers, ABS, and polyvinyl chloride. Vinyl, poly (meth) acrylic acid alkyl ester, polyvinylidene fluoride, polyvinyl chloride, nylon 12, polyacetal, polycarbonate, ethylene vinyl alcohol copolymer (EVOH), polylactic acid (PLA), polybutylene succinate (PBS), etc. Can be mentioned. Among them, at least one selected from polylactic acid, polybutylene succinate, ethylene vinyl alcohol copolymer, polyethylene terephthalate and polyolefin is preferably used. The resin has a melting point of 100 ° C. or higher and 180 ° C. or lower, is excellent in wettability with a hydrophilic material when melted, and is preferable because the strength of the molded product can be easily obtained.

The thermoplastic resin contained in the hydrophilic material-containing region is preferably a melted thermoplastic resin fiber. A part of the thermoplastic resin fiber may be present in the hydrophilic material-containing region without melting. Examples of the thermoplastic resin fiber before melting include fibers made of the above-mentioned thermoplastic resin. In addition, core-sheath fibers and sheath-type composite fibers are also preferably used. For example, polylactic acid (PLA) / polybutylene succinate (PBS) core-sheath fiber, polypropylene (PP) / polyethylene (PE) core / sheath type composite fiber, polyethylene terephthalate (PET) / PE (PE) core / sheath type. Composite fibers are preferably used.

The content of the thermoplastic resin in the hydrophilic material-containing region is preferably 5% by mass or more, more preferably 20% by mass or more, based on the total mass of the hydrophilic material-containing region. The content of the thermoplastic resin is preferably 95% by mass or less, and more preferably 60% by mass or less. By setting the content of the thermoplastic resin within the above range, the rate of decrease in the compressive strength of the molded product can be increased, and the ease of disposal can be improved. In addition, the water resistance and strength of the hydrophilic material-containing region and the entire molded product can be enhanced.

<Ratio of hydrophilic material to thermoplastic resin>
The content of the hydrophilic material in the hydrophilic material-containing region is preferably 40% by mass or more, more preferably 50% by mass or more, based on the total mass of the content of the hydrophilic material and the thermoplastic resin. It is more preferably 51% by mass or more, further preferably 55% by mass or more, and particularly preferably 60% by mass or more. The content of the hydrophilic material is preferably 90% by mass or less, more preferably 80% by mass or less, based on the total mass of the content of the hydrophilic material and the thermoplastic resin. The hydrophilic material is preferably pulp fiber, and in this case, the content of pulp fiber is also preferably in the above range.

<Other ingredients>
The hydrophilic material-containing region may contain a binder component as another component. The binder component may be contained so as to be 0.1% by mass or more and 45% by mass or less with respect to the total mass of the hydrophilic material-containing region, and may be contained so as to be 0.3% by mass or more and 40% by mass or less. It may be contained so as to be 0.4% by mass or more and 35% by mass or less, and may be contained so as to be 0.5% by mass or more and 30% by mass or less. By setting the content of the binder component within the above range, it is possible to improve the handleability and the like when manufacturing the molded product.

Binder components include polyester resins such as various starches, caseins, sodium alginates, hydroxyethyl celluloses, carboxymethyl celluloses, polyethylene terephthalates, and modified polyethylene terephthalates, and core-sheath-type binder fibers (core-sheath PET) and acrylic resins that combine these. Styrene- (meth) acrylic acid ester copolymer resin, urethane resin, polyvinyl alcohol (PVA) resin, various starches, cellulose derivatives, sodium polyacrylic acid, polyacrylamide, polyvinylpyrrolidone, acrylamide-acrylic acid ester-methacrylic acid ester Polymer, styrene-maleic anhydride copolymer alkali salt, isobutylene-maleic anhydride copolymer alkali salt, polyvinyl acetate resin, styrene-butadiene copolymer, vinyl chloride-vinyl acetate copolymer, ethylene-vinyl acetate Copolymers, styrene-butadiene- (meth) acrylic acid ester copolymers and the like can be used.

The hydrophilic material-containing region may further contain a filler or a paper-making chemical. Examples of the filler include kaolin, calcined kaolin, calcium carbonate, calcium sulfate, barium sulfate, titanium dioxide, talc, zinc oxide, alumina, magnesium carbonate, magnesium oxide, silica, white carbon, bentonite, zeolite, sericite, smectite and the like. Examples thereof include mineral pigments and organic pigments such as polystyrene resins, urea resins, melamine resins, acrylic resins and vinylidene chloride resins.
Examples of paper-making chemicals include paper strength enhancers, yield improvers, drainage improvers, dyes, fluorescent whitening agents, pH adjusters, defoaming agents, pitch control agents, slime control agents and the like. Examples of the paper strength enhancer include polyacrylamide and the like. Further, a wet paper strength enhancer can also be used in combination, and examples thereof include polyamide resin, melamine-formaldehyde resin, urea-formaldehyde resin, polyamide-polyamine-epicchlorohydrin resin, and polyethyleneimine resin.

(Resin area)
The molded product of the present invention may have a resin region on at least one surface side of the hydrophilic material-containing region. The molded product of the present invention can increase the strength of the molded product by having a resin region on at least one surface side of the hydrophilic material-containing region. Further, the resin region can enhance the water resistance of the surface of the molded product, further enhance the smoothness and glossiness of the surface of the molded product, and can improve the design.

The resin region includes a thermoplastic resin. The content of the thermoplastic resin contained in the resin region is preferably 60% by mass or more, more preferably 70% by mass or more, based on the total mass of the resin region. Moreover, the resin region may be composed only of a thermoplastic resin.

The resin region preferably contains a resin having a melting point of 200 ° C. or lower. The melting point of the thermoplastic resin is more preferably 195 ° C. or lower, and more preferably 180 ° C. or lower. The melting point of the resin contained in the resin region is preferably 80 ° C. or higher, more preferably 90 ° C. or higher, and even more preferably 100 ° C. or higher. By setting the melting point of the resin contained in the resin region within the above range, deterioration of the hydrophilic material contained in the region containing the hydrophilic material to be laminated can be suppressed, and the water resistance and strength of the molded product can be enhanced. be able to.

Examples of the thermoplastic resin constituting the resin region include polyesters such as polyolefin resins, polystyrenes and polyethylene terephthalates (eg, amorphous PET), acrylonitrile-styrene copolymers, ABS, polyvinyl chlorides and polys (meth). Examples thereof include acrylic acid alkyl esters, polyvinylidene fluorides, nylon 12, polyacetals, polycarbonates, ethylene vinyl alcohol copolymers, and polylactic acid. Among them, at least one selected from the group consisting of polyolefin, polyvinyl chloride, ethylene vinyl alcohol copolymer, polylactic acid and polyethylene terephthalate is preferably used. Further, as the thermoplastic resin of the present invention, it is more preferable to use a polyolefin-based resin, and as the polyolefin-based resin, polyethylene, polypropylene, and acid-modified polypropylene are preferably used, and polypropylene is particularly preferably used.

In the resin area, if necessary, flame retardants, deodorants, antibacterial agents, air fresheners, moisturizers, hygroscopic agents, water absorbents, adsorbents, colorants, hydrophilic agents, water repellents, coupling agents, etc. The function may be imparted by using an agent. As a method for imparting the function, for example, one or a plurality of these agents may be mixed in the resin region in the form of powder. Alternatively, the above agent may be sprayed or impregnated in a liquid state.

The thickness of the resin region is preferably 5 μm or more, more preferably 10 μm or more, and further preferably 20 μm or more. Further, the thickness of the resin region is preferably 100 μm or less. By setting the thickness of the resin region within the above range, it is possible to obtain a molded product having sufficient strength in a dry state, but can be easily compressed and deformed in a wet state.

(Manufacturing method of molded product)
The present invention also relates to a method for producing a molded product, which comprises a step of molding a molded product sheet containing a hydrophilic material and a thermoplastic resin. Here, the forming step comprises at least one step selected from steps of process and pressure forming and vacuum forming, the density is to mold the larger 1.00 g / cm ³ or less of the molding than 0.20 g / cm ³ It is a process. In the method for producing a molded product of the present invention, by including the above-mentioned molding step, when the compressive strength of the molded product when dry is P and the compressive strength of the molded product when wet is Q, the following A molded product having a compressive strength reduction rate (%) calculated by the formula (1) of 10% or more can be produced.
Decrease rate (%) = (1-Q / P) x 100 formula (1)

In the method for producing a molded product of the present invention, a molded product sheet containing a hydrophilic material and a thermoplastic resin is molded by at least one step selected from a vacuum molding step and a pressure molding step. It can be easily processed into the desired shape of the molded product. In the method for producing a molded product of the present invention, a molded product having a complicated shape can be molded, and for example, deep drawing molding can be easily performed.

Here, in the present invention, the hydrophilic material is preferably pulp fiber. When the molded product of the present invention contains a resin region, in the manufacturing process of the molded product, a resin sheet is obtained by laminating a fiber-containing plastic molded product sheet containing pulp fibers and a thermoplastic resin and a resin sheet. It is preferable to include a step of obtaining a sheet for a molded body containing a resin sheet and a step of molding the sheet for a molded body containing a resin sheet by at least one step selected from a step of vacuum molding and a step of pressure molding.

The step of laminating the fiber-containing plastic molded product sheet and the resin sheet may be a step of simply laminating the fiber-containing plastic molded product sheet and the resin sheet to form a stacked body. Further, the step of laminating the fiber-containing plastic molded sheet and the resin sheet may be a step of laminating the fiber-containing plastic molded sheet and the resin sheet and prepressing them into a stacked body. Such a stacked body is preferably used in the stamping molding step described later. On the other hand, the step of laminating the fiber-containing plastic molded sheet and the resin sheet may be a step of laminating the fiber-containing plastic molded sheet and the resin sheet via an adhesive layer to form a laminated body.

When the fiber-containing plastic molded sheet and the resin sheet are laminated and prepressed, the prepress is preferably performed under low pressure conditions. For example, it is preferable to heat the thermoplastic resin contained in the fiber-containing plastic molded sheet in the range of ± 30 ° C. of the melting point and pressurize under a pressure condition of 0.1 MPa or more and 5 MPa or less.

The fiber-containing plastic molded sheet can be laminated individually or to a desired thickness, and the thickness and strength of the molded body can be adjusted by adjusting the number of laminated sheets.

The molding step is preferably at least one step selected from a press molding step, a vacuum forming step, and a pressure forming step, and is at least one step selected from a vacuum forming step and a pressure forming step. Is more preferable. Further, these molding steps may be a combination of a plurality of molding steps, and a plurality of steps may be carried out at the same time to form one step.

When the molding step is a press molding step, the press molding step is a heat and pressure molding step. In the step of heat and pressure molding, it is preferable to heat a laminated sheet of a fiber-containing plastic molded body and a resin sheet to 100 ° C. or higher. The heating temperature in the step of heat-press molding is preferably 100 ° C. or higher, but it is preferably adjusted appropriately depending on the type of the thermoplastic resin contained in the fiber-containing plastic molded sheet. Specifically, it is preferable to heat within the range of ± 20 ° C. of the melting point of the thermoplastic resin contained in the fiber-containing plastic molded sheet. When polylactic acid is used as the thermoplastic resin, the heating temperature is preferably 150 ° C. or higher and 180 ° C. or lower, and more preferably 160 ° C. or higher and 180 ° C. or lower. By performing heat molding within such a temperature range, thermal decomposition (decomposition of hemicellulose) of pulp fibers contained in the fiber-containing plastic region can be suppressed, and a molded product having higher strength can be obtained. can.

Among the various press molding methods that exist, the heat and pressure molding method includes the autoclave method, which is often used when manufacturing molded parts such as large aircraft, and the mold press, which has a relatively simple process. The method is preferred. The autoclave method is preferable from the viewpoint of obtaining a high-quality molded product with few voids. On the other hand, from the viewpoints of energy consumption in equipment and molding process, simplification of jigs and auxiliary materials for molding used, molding pressure, and degree of freedom in temperature, gold that is molded using a metal mold. It is preferable to use a mold pressing method, and these can be selected according to the application.

The press molding step may be a stamping molding step. In the stamping molding method, a sheet in which a fiber-containing plastic molded body sheet and a resin sheet are laminated in advance is heated, and the thermoplastic resin is melted and softened and placed inside the molding mold, and then the mold is closed and the mold is closed. This is a method of tightening and then pressurizing and cooling. For heating, a heating device such as a far-infrared heater, a heating plate, a high-temperature oven, or dielectric heating can be used. Further, when the temperature at the time of molding is relatively low, such as when obtaining a molded product having a low density, the hot press method can also be adopted.

The molding step may be a vacuum forming step. In vacuum forming, it is possible to improve the adhesion between the sheet and the mold and improve the moldability by creating a vacuum state between the laminated sheet for the fiber-containing plastic molded body and the resin sheet and the mold. can. Vacuum forming is preferably performed in the mold clamping step of the stamping molding step described above. Specifically, a sheet in which a fiber-containing plastic molded body sheet and a resin sheet are laminated in advance is heated, and the thermoplastic resin is melted and softened and placed inside the molding die, and then the mold is closed and the mold is closed. Vacuum forming is performed in the tightening process. In vacuum forming, vacuum suction is performed from the molding die side. The molding pressure in vacuum forming is usually 1.0 kg / cm ² or less, and molding is performed in about 0.1 seconds or more and 60 seconds or less. By adopting the vacuum forming step in the molding step, for example, deep drawing molding and molding of a complicated shape become easy.

The molding step may be a compressed air molding step. In pneumatic molding, compressed air is blown onto a laminated sheet for a fiber-containing plastic molded body to bring it into close contact with the mold, thereby improving the adhesion between the sheet and the mold. Compressed air molding is preferably performed in the mold clamping step of the stamping molding step described above. Specifically, a sheet in which a fiber-containing plastic molded body sheet and a resin sheet are laminated in advance is heated, and the thermoplastic resin is melted and softened, placed in a molding die, and then compressed air is blown from the sheet side. By doing so, molding is performed. Pneumatic molding is often performed with compressed air pressure of 3 kg / cm ² or more and 8 kg / cm ² or less, and molding is performed in about 0.1 seconds or more and 60 seconds or more. By adopting the compressed air molding step in the molding step, for example, deep drawing molding and molding of a complicated shape can be easily performed.

When the step of laminating the fiber-containing plastic molded sheet and the resin sheet is the step of laminating the fiber-containing plastic molded sheet and the resin sheet via the adhesive layer to form a laminated body, the fiber-containing plastic molding An adhesive is applied to the body sheet, and a resin sheet is laminated on the adhesive. It is preferable that the above-mentioned molding step is also applied to the laminated sheets laminated via the adhesive layer.

When the step of laminating the fiber-containing plastic molded sheet and the resin sheet is the step of laminating the fiber-containing plastic molded sheet and the resin sheet via the adhesive layer, the adhesive constituting the adhesive layer may be used. The material is not particularly limited as long as it is a material that follows during molding, but a hot melt type adhesive using a thermoplastic resin is preferable. Examples of such thermoplastic resins include olefin-based, polyamide-based, rubber-based, and polyester-based resins such as ethylene-vinyl acetate copolymers and polypropylene. The hot melt type adhesive is preferably heated above the melting point and coated. A known method can be used as the coating method.

In the present invention, it is preferable that the fiber-containing plastic molded body sheet and the resin sheet are laminated without interposing an adhesive layer, and the stacked body is subjected to the above-mentioned molding step. In this case, the molding step is a step of joining the fiber-containing plastic molded body sheet and the resin sheet. That is, at the time when the fiber-containing plastic molded body sheet and the resin sheet are laminated, both sheets are not completely joined (bonded), and both sheets are completely joined (bonded) by heat and pressure molding.
When a fiber-containing plastic molded sheet and a resin sheet are laminated via an adhesive layer to form a laminate, and the laminate is subjected to a molding process, the fiber-containing plastic molded sheet via the adhesive layer is also used. And the adhesion of the resin sheet becomes stronger.

<Sheet for molded body>
The molded article sheet used in the molding article manufacturing process of the present invention contains a hydrophilic material and a thermoplastic resin fiber. When the hydrophilic material is pulp fiber, the sheet for molded article may be referred to as a sheet for fiber-containing plastic molded article.

The thermoplastic resin contained in the sheet for the molded body may be in any form, and examples thereof include fibers and powders made of the above-mentioned thermoplastic resin. A liquid made of a thermoplastic resin may be sprayed or coated on the sheet to be blended. Further, as the thermoplastic resin fiber, a core sheath fiber or a sheath type composite fiber is also preferably used. For example, polylactic acid (PLA) / polybutylene succinate (PBS) core-sheath fiber, polypropylene (PP) / polyethylene (PE) core / sheath type composite fiber, polyethylene terephthalate (PET) / PE (PE) core / sheath type. Composite fibers are preferably used.

The thermoplastic resin fiber used in the present invention is preferably chopped strands cut to a certain length. The fiber length of the thermoplastic resin fiber is preferably 2 mm or more and 50 mm or less, more preferably 5 mm or more and 40 mm or less, and further preferably 10 mm or more and 25 mm or less. By setting the fiber length of the thermoplastic resin fiber within the above range, it is possible to prevent the thermoplastic resin fiber from falling off when forming the hydrophilic material-containing region, and to obtain a molded product having excellent strength. It becomes possible to form. Further, by setting the fiber length of the thermoplastic resin fiber within the above range, the dispersibility of the thermoplastic resin fiber can be improved.

The molded product sheet may contain powder, granular, and pellet-shaped thermoplastic resins in addition to the thermoplastic resin fibers. Further, a binder component other than the thermoplastic resin may be contained.

The basis weight of the molded product sheet ^{is preferably 100 g / m 2} or more, more preferably 150 g / m ² or more, further preferably 200 g / m ² or more, and 220 g / m ² or more. It is more preferable to have. The upper limit of the basis weight of the molded product sheet is not particularly limited, but may be, for example, 3000 g / m ² . By setting the basis weight of the sheet for the molded product within the above range, the compressive strength at the time of drying can be increased, and a molded product having excellent strength can be obtained.

The density of the molded product sheet ^{is preferably higher than 0.10 g / cm 3, and} more preferably 0.20 g / cm ³ or more. The density of the sheet for the molded body ^{is preferably 1.00 g / cm 3} or less, more preferably 0.80 g / cm ³ or less, and ^{further preferably 0.70 g / cm 3} or less. , 0.60 g / cm ³ or less is particularly preferable.

<Manufacturing method of molded sheet>
The molded sheet is manufactured by using a wet or dry sheet forming method. In the following, the case where the hydrophilic material is pulp fiber will be described on behalf of the process of manufacturing the fiber-containing plastic molded sheet.

When a fiber-containing plastic molded sheet is produced by using the wet papermaking method, thermoplastic resin fibers and pulp fibers, and if necessary, a binder component, a filler, a paper-making chemical, and the like are dispersed in a solvent such as water. Then, the solvent is removed to form a web.

When producing a sheet for a fiber-containing plastic molded body using a wet papermaking method, an acidic papermaking method performed at a pH of around 4.5, an alkaline filler such as calcium carbonate as a main component, and a weak acidity of pH 6 A neutral papermaking method or the like performed with a weak alkalinity of pH 9 can be adopted. As the paper machine, a long net paper machine, a twin wire paper machine, a circular net paper machine, an inclined wire type paper machine, a single net paper machine, a Yankee paper machine and the like can be appropriately used. In particular, by using a multi-layer paper machine such as a circular net paper machine or a single net paper machine, a sheet for a fiber-containing plastic molded body having a large basis weight can be obtained. Further, by using a multi-layer paper machine, the formulation of each layer can be changed, and a fiber-containing plastic molded sheet having different functions depending on the depth method can be obtained.

When producing a sheet for a fiber-containing plastic molded product by using the dry papermaking method, for example, a method of forming a web by a dry method such as a carding method or an airlaid method can be adopted. The carding method is a method of forming a uniform sheet-like web while mechanically combing fiber ingots. In the air-laid method, an air flow containing a raw material fiber obtained by uniformly mixing thermoplastic resin fibers and pulp fibers defibrated in air in an air flow is discharged onto a mesh-shaped endless belt provided with a suction box on the lower side. It is a method of forming an air-laid web.

The web formed by the dry method is sheeted by a fiber bonding step as shown below. As a fiber bonding step, for example, there is a method such as a needle punching method in which thermoplastic resin fibers and pulp fibers are entangled with each other by passing a needle in a direction perpendicular to a web surface to form a sheet. Such a bonding step is preferably used in combination with a web forming method by a carding method. Further, in the fiber bonding step, a step of fusing the heat-sealing adhesive blended in the dry web by heating to bond the raw material fibers (thermal bond method), and applying an adhesive to the obtained dry web. Then, a step of bonding the raw material fibers (chemical bond method) or a method of combining the thermal bond method and the chemical bond method (multi-bond method) can be adopted.

In the thermal bond method, it is preferable to heat at a temperature 20 ° C. or higher higher than the melting point of the heat-sealing adhesive. Examples of the heat treatment include hot air treatment and hot pressure treatment with a low pressure after the hot air treatment.

When the thermal bond method or the multi-bond method is adopted, it is preferable to use a particulate or fibrous heat-sealing adhesive. The heat-sealing adhesive may be the above-mentioned thermoplastic resin or binder component. As the particulate heat-sealing adhesive, heat-sealing resin particles such as polyethylene, polypropylene, polyester low melting point polyethylene terephthalate, low melting point polyamide, low melting point polylactic acid, and polybutylene succinate are used. Examples of the fibrous heat-sealing adhesive include polyesters such as low melting point polyethylene terephthalate, low melting point polylactic acid, polybutylene succinate, and polyethylene terephthalate (PET), polyethylene (PE), polypropylene (PP), and low melting point polyamide. , Acrylic resin, vinyl acetate (PVAc) resins are used. Further, as the heat-sealing synthetic fiber, a heat-sealing composite synthetic fiber having a core-sheath structure obtained by combining two types of resins having different melting points and melting only the surface of the fiber is preferably used. can. The heat-sealing composite synthetic fiber having a core-sheath structure has a structure in which a sheath made of a resin having a low melting point is formed on the outer periphery of a core made of a resin having a high melting point. Specifically, a form in which two types of resins having different melting points are combined (PET / PET composite fiber, PE / PE composite fiber, PP / PP composite fiber, PE / PET composite fiber, PP / PET composite fiber, PE / PP Composite fibers, PVAc / PET composite resins).

Further, when the chemical bond method is used for bonding the fibers, it is preferable to add a binder component in order to fix the fibers to each other. The binder component can be appropriately selected as needed, and examples thereof include solution-type binders such as starch, casein, sodium alginate, hydroxyethyl cellulose, sodium carboxymethyl cellulose salt, polyvinyl alcohol (PVA), and sodium polyacrylic acid. Polyacrylic acid ester, acrylic-styrene copolymer, polyvinyl acetate, ethylene-vinyl acetate copolymer, acrylic nitrile-butadiene copolymer, methyl methacrylate-butadiene copolymer, urea-melamine resin, styrene-butadiene Emulsion-type binders such as polymer resins can be used. It is also preferable to use the binder component described above. As the above-mentioned binder, various forms such as fibers, powders, granules, solutions and emulsions can be used, and two or more kinds can be used in combination.

When a fiber-containing plastic molded sheet is produced by using a wet papermaking method or a dry papermaking method, a calendar treatment may be performed after the heat treatment for the purpose of improving smoothness and controlling the density, if necessary. In the calendering process, the density of the sheet can be arbitrarily controlled by pressurizing with a metal roll or a resin roll. Further, by setting the roll for calendar processing to an arbitrary temperature and heating and pressurizing the sheet, a highly smooth and high-density sheet can be obtained.

In the fiber-containing plastic molded sheet produced by the dry papermaking method, each fiber constituting the fiber-containing plastic molded sheet is randomly three-dimensionally oriented in the longitudinal direction, the width direction, and the thickness direction. In the present invention, such a sheet for a fiber-containing plastic molded product is also preferably used.

In the process of manufacturing a sheet for a fiber-containing plastic molded product, an arbitrary sheet that does not impair moldability may be laminated on the sheet for a fiber-containing plastic molded product to produce a laminated sheet. For example, any sheet can be laminated on the surface of the fiber-containing plastic molded sheet or between the sheets when the fiber-containing plastic molded sheet is laminated. As an arbitrary sheet to be laminated, a sheet such as a tissue or a non-woven fabric can be used. These arbitrary sheets are laminated for the purpose of improving surface properties, improving interlayer strength, and imparting other functions.

<Resin sheet>
When a resin sheet is used in the manufacturing process of the molded product of the present invention, the resin sheet contains a thermoplastic resin. The content of the thermoplastic resin contained in the resin sheet is preferably 60% by mass or more, more preferably 70% by mass or more, based on the total mass of the resin sheet. Further, the resin sheet may be composed of only a thermoplastic resin.

The melting point of the thermoplastic resin constituting the resin sheet is preferably 200 ° C. or lower. The melting point of the thermoplastic resin is more preferably 195 ° C. or lower, and more preferably 180 ° C. or lower. The melting point of the resin constituting the resin sheet is preferably 80 ° C. or higher, more preferably 90 ° C. or higher, and even more preferably 100 ° C. or higher. By setting the melting point of the resin constituting the resin sheet within the above range, it is possible to prevent the pulp fibers contained in the laminated fiber-containing plastic molded sheet from deteriorating, and the water resistance and design of the molded body can be suppressed. And strength can be increased.

Examples of the thermoplastic resin constituting the resin sheet include the thermoplastic resin in the resin constituting the resin region described above. Among them, at least one selected from the group consisting of polyolefin resins, polyvinyl chloride, ethylene vinyl alcohol copolymers, polylactic acid and polyethylene terephthalate is preferably used. Further, as the thermoplastic resin of the present invention, it is more preferable to use a polyolefin-based resin. The form of the resin sheet is preferably a film or a non-woven fabric.
The resin sheet is a film or a non-woven fabric, and the thermoplastic resin constituting the resin sheet is at least one selected from the group consisting of polyolefin resins, polyvinyl chlorides, ethylene vinyl alcohol copolymers, polylactic acid and polyethylene terephthalates. It is preferably present, and more preferably a polyolefin-based resin film or a non-woven fabric made of a polyolefin-based resin. As the polyolefin-based resin, polyethylene, polypropylene, and acid-modified polypropylene are preferably used, and polypropylene is particularly preferably used.

If necessary, the resin sheet may contain flame retardants, deodorants, antibacterial agents, air fresheners, moisturizers, hygroscopic agents, water absorbents, adsorbents, heat retaining agents, colorants, hydrophilic agents, water repellents, and couplings. The function may be imparted by using an agent such as an agent or a design imparting agent. The function-imparting agent may be an inorganic material or an organic material. As a method of adding the function-imparting agent, for example, one or a plurality of these agents may be kneaded with the resin at the time of sheet molding, or the above agent may be added by a method such as coating after sheet molding.

(Use)
The molded body of the present invention includes electrical / electronic equipment, OA equipment, electrical equipment, civil engineering / construction, automobiles, aircraft parts, structural parts and housings, containers (for example, food containers, chemical packaging containers), furniture, and sun. It is preferably used for general merchandise, medical equipment, etc.

The features of the present invention will be described in more detail with reference to Examples and Comparative Examples. The materials, amounts used, ratios, treatment contents, treatment procedures, etc. shown in the following examples can be appropriately changed as long as they do not deviate from the gist of the present invention. Therefore, the scope of the present invention should not be construed as limited by the specific examples shown below.

<Example 1>
A high cloth with a basis weight of 80 g / m ² (pulp made by Oji Kinocross Co., Ltd .: synthetic fiber ratio = 50: 50) is fed onto a running endless mesh conveyor, and raw material fibers are placed on the air-laid web. A web was formed by dropping and accumulating at ^{100 g / m 2} together with an air flow by a forming machine. The raw material fibers include pulp (NBKP) and PP / PE core-sheath composite fiber (manufactured by Chisso Co., Ltd., trade name: ETC, melting point 130 ° C., fiber thickness 13 μm, fiber length: 5 mm) at 60:40. Was mixed in the mass ratio of the above, and the mixture prepared by mixing uniformly in the air was used.
Next, the tissue was fed out on the formed web, the obtained web was passed through a through air dryer having a temperature of 140 ° C., and then pressed with a roll press having a clearance set to 1 mm at a linear pressure of 2 MPa to hot melt. The resin is applied so as to be 5 g / m ^2, and a 40 μm CPP film (manufactured by Hokuetsu Kasei Co., Ltd., unstretched polypropylene film, thickness 40 μm) is bonded to the sheet for a molded ^{product having a basis weight of 239 g / m 2.} A was prepared.

(Molding process of molded body)
The sheet A for a molded body was cut into 30 cm squares, heated at a surface temperature of 150 ° C. for 10 seconds, sandwiched between metal plates, and pressed at 0.5 MPa for 10 seconds to prepare a plate-shaped molded body.

<Example 2>
^{A molded body sheet B having a basis weight of 239 g / m 2} was prepared in the same manner as in Example 1 except that the ratio of pulp (NBKP) and PP / PE core-sheath composite fiber was changed to 50:50. A molded product was obtained in the same manner as in 1.

<Example 3>
A sheet C for a molded body having a basis weight of 289 g / m ² was produced in the same manner as in Example 2 except that the raw material fibers were ^{dropped and deposited so as to be 150 g / m 2,} and molded in the same manner as in Example 1. I got a body.

<Example 4>
^{A molded body sheet D having a basis weight of 289 g / m 2} was prepared in the same manner as in Example 3 except that the ratio of pulp (NBKP) and PP / PE core-sheath composite fiber was changed to 40:60. A molded product was obtained in the same manner as in 1.

<Example 5>
A tissue with a basis weight of 14 g / m ² is delivered on a running endless mesh conveyor, and raw material fibers are dropped and deposited on the tissue by an air-laid web forming machine so as to have an air flow of 150 g / m ^2. Formed the web. The raw material fibers include pulp (NBKP) and PP / PE core-sheath composite fiber (manufactured by Chisso Co., Ltd., trade name: ETC, melting point 130 ° C., fiber thickness 13 μm, fiber length: 5 mm) at 60:40. Was mixed in the mass ratio of the above, and the mixture prepared by mixing uniformly in the air was used. Next, the tissue is fed out on the formed web, the obtained web is passed through a through air dryer having a temperature of 140 ° C., and then pressed, and the front and back surfaces are peeled off to form a molded product ^{having a basis weight of 150 g / m 2.} Sheet E was prepared. Further, a molded product was obtained in the same manner as in Example 1.

<Example 6>
^{A molded product sheet F having a basis weight of 225 g / m 2} was produced in the same manner as in Example 1 except that the tissue was not fed out on the formed web, and a molded product was obtained in the same manner as in Example 1.

<Example 7>
For a molded product having a basis weight of 275 g / m ^{2 in} the same ^{manner as in Example 1 except that the raw material fibers were dropped and deposited together with the air flow to a concentration of 150 g / m 2} by an air-laid web forming machine to form a web. Sheet G was produced, and a molded product was obtained in the same manner as in Example 1.

<Example 7a>
An aluminum lid material (made of Toyo Aluminum, thickness 15 μm, for PP heat sealing) was heat-bonded to the high cloth surface of the molded body obtained in Example 7 to obtain a molded body to which the lid material was bonded.

<Example 7b>
A paper lid material (manufactured by Oji F-Tex, thick-mouthed glassine: basis weight 30.5 g / m2) is heat-bonded to the high cloth surface of the molded body obtained in Example 7 to obtain a molded body to which the lid material is bonded. rice field.

<Example 8>
The ratio of pulp (NBKP) and PP / PE core-sheath composite fiber was changed to 70:30, and the raw material fiber was dropped and deposited ^{with an air flow to 200 g / m 2 with an air-laid web forming machine. A sheet H for a molded product having a basis weight of 325 g / m 2} was produced in the same manner as in Example 1 except that the above-mentioned material was formed, and a molded product was obtained in the same manner as in Example 1.

<Example 9>
The PE resin was laminating on the high cloth of the molded body sheet G obtained in Example 7 so as to have a thickness of 20 μm ^{to prepare a molded body sheet I having a basis weight of 290 g / m 2} , and the same as in Example 1. To obtain a molded product.

<Example 10>
PLA / PBS core-sheath composite fiber was used instead of PP / PE core-sheath composite fiber, and the ratio of pulp to PLA / PBS core-sheath composite fiber was changed to 54:46. A sheet J for a molded body having an amount of 150 g / m ² was prepared, and a molded body was obtained in the same manner as in Example 1.

<Example 11>
PLA / PBS core-sheath composite fiber and EVOH fiber are used instead of PP / PE core-sheath composite fiber, and the ratio of pulp to PLA / PBS core-sheath composite fiber and EVOH fiber is changed to 32:59:10. A sheet for a molded body having a basis weight of 185 g / m ^{2 in the same manner as in Example 5, except that the fibers were dropped and deposited together with an air flow to a concentration of 185 g / m 2} by an air-laid web forming machine to form a web. K was produced, and a molded product was obtained in the same manner as in Example 1.

<Example 12>
A molded sheet L having ^{a basis weight of 239 g / m 2} was prepared in the same manner as in Example 2 except that the PET / PE core-sheath composite fiber was used instead of the PP / PE core-sheath composite fiber. A molded product was obtained in the same manner.

<Example 13>
A molded article sheet M having a basis weight of 218 g / m ^{2 was prepared in the same manner as in Example 1 except that PE was applied so as to be 15 g / m 2} instead of laminating the CPP film with a hot melt resin. A molded product was obtained in the same manner as in Example 1.

<Example 14>
Same as in Example 4 except that half of the pulp (NBKP) was replaced with PVA fiber (manufactured by Vinylon Kuraray) and the ratio of pulp: PVA fiber: PP / PE core-sheath composite fiber was changed to 20:20:60. A sheet N for a molded body having a basis weight of 289 g / m ² was prepared, and a molded body was obtained in the same manner as in Example 1.

<Comparative example 1>
The molded product sheet J obtained in Example 10 was heated at a surface temperature of 150 ° C. for 10 seconds, sandwiched between metal plates, and pressed at 10 MPa for 10 minutes to obtain a molded product in the same manner as in Example 1. rice field.

<Comparative example 2>
A commercially available PVC film having a basis weight of 350 g / m ² was used as a sheet for a molded product, and a molded product was obtained in the same manner as in Example 1.

<Comparative example 3>
A commercially available PP film having a basis weight of 450 g / m ² was used as a sheet for a molded product, and a molded product was obtained in the same manner as in Example 1.

<Comparative example 4>
A commercially available PP film having a basis weight of 337.5 g / m ² was used as a sheet for a molded product, and a molded product was obtained in the same manner as in Example 1.

(Evaluation of compressive strength)
Paper and paperboard of JIS P 8126-Compressive strength when dry and 1 in water using a sample cut out from the obtained molded product to 12.7 mm × 152.4 mm according to the compressive strength test method (ring crush method). The compressive strength (compressive strength when wet) after the minute immersion was measured. Then, the rate of decrease in compressive strength (%) was calculated using the following formula.
Decrease rate (%) = (1-Compressive strength when wet / Compressive strength when dry) x 100

It was confirmed that the molded product obtained in the examples had a high rate of decrease in compressive strength, excellent compressibility at the time of disposal, and a high degree of freedom in shape change when wet.

In Example 7, the water absorption was also evaluated. The water absorption was determined according to JIS P 8141 paper and paperboard-water absorption test method (Krem method). A measurement sample obtained by PE laminating the surface (high cross surface) of the molded body obtained in Example 7 was cut out to a size of 15 mm × 200 mm so that a region of 15 mm from one end in the longitudinal direction of the sample was immersed in water. The height (mm) of the water rising was measured by suspending the sample and hanging the sample for 10 minutes. As a result, the measurement result of the water absorption of the molded product of Example 7 was 153 mm.

From the molded body sheet obtained in the examples, molded bodies having various shapes could be molded. For example, a dome-shaped molded product and a bat-shaped molded product could be molded from the molded product sheet of the example by the following method.
At the time of molding, one sheet for a molded body obtained in the example was fixed to the frame of the molding apparatus by using a molding machine including a heating zone and a pressure molding zone. After heating for 15 seconds (so that the surface temperature of the sheet is 145 ° C) with the temperature setting of the far-infrared heating device in the heating zone set to 300 ° C, the height from the bottom surface is 1.5 cm and the diameter in the molding zone. Pressure molding was performed by a stamping method using a 5 cm dome-shaped uneven mold to obtain a dome-shaped molded product. In addition, the bottom surface is a rectangle of 12 cm x 15 cm, the corner radius is set to 8.4, the height from the bottom surface is 1 cm, and the circumference is 2 cm. Pressure molding was performed to obtain a butt-shaped molded product.

10 Molded product 12 Hydrophilic material-containing region 14 Resin region

Claims (7)

A molded product containing a hydrophilic material and a thermoplastic resin.
The hydrophilic material is pulp fiber
The melting point of the thermoplastic resin is 200 ° C. or lower, and the temperature is 200 ° C. or lower.
The density of the molded product ^{is greater than 0.10 g / cm 3 and} 1.00 g / cm ³ or less.
When the compressive strength of the molded product when dry is P and the compressive strength of the molded product when wet is Q, the compressive strength reduction rate (%) calculated by the following formula (1) is A molded product that is 10% or more.
Decrease rate (%) = (1-Q / P) x 100 formula (1) A fiber-containing plastic region containing the pulp fiber and the thermoplastic resin,
The molded product according to claim 1 , further comprising a resin region in contact with at least one surface side of the fiber-containing plastic region. The molded product according to claim 2 , wherein the content of the pulp fiber is 40% by mass or more with respect to the total mass of the content of the pulp fiber and the thermoplastic resin. The molded product according to claim 2 or 3 , wherein the resin region contains a resin having a melting point of 200 ° C. or lower. The molded product according to any one of claims 1 to 4 , wherein the thermoplastic resin is at least one selected from polylactic acid, polybutylene succinate, ethylene vinyl alcohol copolymer, polyethylene terephthalate and polyolefin. A method for producing a molded product, which comprises a step of molding a molded product sheet containing a hydrophilic material and a thermoplastic resin.
The hydrophilic material is pulp fiber
The melting point of the thermoplastic resin is 200 ° C. or lower, and the temperature is 200 ° C. or lower.
The molding step includes at least one step selected from a vacuum forming step and a compressed air molding step.
Said step of forming is a step density is formed largely 1.00 g / cm ³ or less of the molding than 0.20 g / cm ^3,
When the compressive strength of the molded product when dry is P and the compressive strength of the molded product when wet is Q, the compressive strength reduction rate (%) calculated by the following formula (1) is A method for producing a molded product having a content of 10% or more.
Decrease rate (%) = (1-Q / P) x 100 formula (1) The molding step is
A step of laminating a fiber-containing plastic molded product sheet containing the pulp fiber and the thermoplastic resin and a resin sheet to obtain a resin sheet-containing molded product sheet.
The method for producing a molded product according to claim 6 , further comprising a step of molding the resin sheet-containing molded product sheet by at least one step selected from a vacuum forming step and a pressure molding step.

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