JPH108393A - Press forming paper - Google Patents

Abstract

(57) [Problem] To provide a press-formed paper which can smoothly produce a press-formed product such as a deep-drawn container without breaking even when hot press-molding is performed in a dry state.
And a method capable of smoothly producing a molded article by press molding using the press molded paper. SOLUTION: The content ratio of natural pulp: thermoplastic polymer fiber is 99: 1 to 50:50 (weight ratio), and the thermoplastic polymer fiber has a thermal adhesive property at a press molding temperature and a fiber elongation. The above object can be achieved by the press-formed paper of the present invention using a thermoplastic polymer fiber having a degree of 20 to 70% and press-forming using the press-formed paper.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a press-formed paper, a method for producing a molded product by performing hot press molding using the press-formed paper, and a press-formed product obtained by the method. More specifically, the present invention is to provide a method for producing a deep drawn product having a depth of as much as 50 mm and having complicated irregularities by press molding without causing breakage of paper. The present invention relates to a press-formed paper mainly made of natural pulp, a method for producing a molded product by press molding using the press-formed paper, and a press-formed product obtained thereby.

[0002]

2. Description of the Related Art Conventionally, tray containers for food packaging, packaging containers for electric / electronic parts and other industrial parts have been conventionally used.
Plastic containers such as containers made by pressing foamed polystyrene sheets, containers made by molding foamed polystyrene beads, and containers made using polyvinyl chloride sheets and foams are easy to manufacture. It has been widely used because of its characteristics, mass production, economical efficiency, and so on. However, plastic containers have various problems, such as the generation of harmful gases when incinerated after their use, the generation of high heat during incineration, shortening the life of the incinerator, and remaining undecomposed even when landfilled. In recent years, the processing of used plastic has become a major social problem.

[0003] In view of the above, the above-mentioned packaging containers which have been conventionally produced from plastics have been manufactured by using pulp. For example, egg packaging containers and fruit packaging containers have been used. Pulp containers are actually used. However, in general, natural pulp paper has almost no stretchability. Therefore, if press forming or drawing is performed after the paper is manufactured, the paper breaks and the container cannot be manufactured smoothly. Therefore, when manufacturing a container made of paper (made of natural pulp), a mesh having a depression matching the outer shape of the intended container (for example, a mesh having a concave portion matching the outer shape of an egg) is prepared. Generally, a method of manufacturing (molding) a paper container by wet-making a papermaking raw material including pulp using the mesh pattern, followed by drying. However, the above-mentioned wet molding method requires time and labor in the production of paper containers, resulting in extremely low productivity, which is one reason that the paper containers are not widely used.

Therefore, in order to manufacture paper containers with high productivity, instead of the above-described method for manufacturing paper containers using a mesh, (1) a synthetic pulp of a thermoplastic resin or natural pulp from the synthetic pulp. A method of manufacturing a molded product by subjecting a sheet to a two-dimensional wrinkle in advance and then hot press molding the molded product
(3265 publication); (2) A method of manufacturing a molded article for packaging by forming corrugated paper from a resin-treated paper material and performing press molding while stretching the corrugated bent portion of the corrugated paper (Japanese Patent Laid-Open No. Hei 5 −2860
JP-A-7-214705); and (3) a method in which a plurality of humidified base papers are superimposed via an adhesive material, and wrinkles are applied thereto, followed by press molding to produce a flat plate molded product (JP-A-7-214705). ); Has been proposed.

In the conventional method (1), synthetic pulp such as polyethylene or polypropylene is actually used for 5 times.
2. Description of the Related Art Hot press molding is performed using a sheet having two-dimensional wrinkles obtained by papermaking a raw material containing 100 to 100% and a natural pulp at a ratio of 95 to 0%. However, sheets with wrinkles made of synthetic pulp such as polyethylene or polypropylene are not sufficiently stretchable during hot press molding, and produce deep drawn molded products with a depth of 50 mm and complex irregularities. In such a case, a hole or tear is generated at a corner or the like of the molded product, and a deep drawn molded product cannot be manufactured smoothly.

In the case of the conventional method (2),
Although the paper material is formed with corrugated irregularities to give a stretch allowance to the paper material during hot press molding, the formation of the corrugated irregularities alone does not provide sufficient stretchability of the paper material during hot press molding.
Therefore, in practice, a method has been adopted in which a paper material provided with corrugations at the time of hot press molding is moistened to increase its elongation and then hot press molding is performed. Therefore, it is necessary to perform a process of rewetting the paper material obtained by drying after wet papermaking, which is complicated in the process. After the hot press molding, the wet paper material needs to be dried, and as a result, extra heat and labor are required. Moreover, in the conventional method of (2), the above-described formation of the wavy irregularities is performed while heating the paper material obtained by drying after wet papermaking, so that the formation of the wavy irregularities is performed. Requires extra steps and heating.

In the case of the conventional method (3), the base paper is humidified as it is, or the base paper is humidified with a polyethylene laminate layer provided on at least one side thereof, and a plurality of the base papers are superposed. Since press forming is performed after the wrinkles are applied, a process of humidifying the base paper is required, and the process becomes complicated.
In addition, since the humidified laminate of base paper is hot-pressed, it must be dried during or after hot-pressing, which results in reduced productivity and high cost in terms of process and thermal efficiency. Inviting. In addition, in the case of the conventional method (3), since the base paper portion is basically made of only natural pulp, it can be said that wrinkles are provided, but the stretchability during hot press molding is sufficient. It is practically difficult to produce a deep-drawn molded product having a depth as high as 50 mm, which is not high, without breaking.

[0008] In addition to the above-mentioned conventional techniques (1) to (3), paper containers made by press molding include:
(4) Synthetic resin fibers such as polyethylene and polypropylene and wood pulp are mixed in a ratio of 0: 1 to 1: 1 and 1: 1 to 9:
A paper container made by mixing and papermaking at two ratios of 1 to form two types of synthetic pulp paper, laminating them in two or three layers, and press-molding the same (Japanese Patent Application Laid-Open No. 50-27878);
And (5) a laminate comprising a paper substrate having an elongation of 1.8% or more in the vertical and horizontal directions and a heat-resistant synthetic papermaking paper containing an inorganic filler provided on both sides of the paper substrate via an adhesive layer. 2. Related Art A heat-resistant container made of press-formed paper is known.

However, in the above prior art (4), since the purpose is to improve the water resistance of the paper container exclusively, no consideration is given to the stretchability of the paper material during press molding. Moreover, since the paper material used in the prior art of (4) is manufactured using synthetic fibers made of polyethylene or polypropylene, as in the conventional method of (1), the stretchability during press molding is increased. However, it is not sufficient, and it is not possible to smoothly manufacture a deep drawn molded product having a depth of 50 mm and having complicated irregularities without breaking or the like.

Further, although the prior art (5) discloses that an organic resin binder can be used at a rate of 0 to 10% at the time of manufacturing a paper substrate, the content of the organic resin binder is not specifically described. Is not described,
The paper substrate actually manufactured by the prior art (5) is a paper substrate composed of only wood pulp. In addition, in the prior art of (5), since the heat-resistant layer having extremely small elongation is formed on the surface of the paper substrate, the stretchability of the entire laminate is extremely small, and therefore, the depth reaches 50 mm, and complicated unevenness is formed. It is not possible to produce a deep-drawn molded product smoothly without breaking or the like.

Further, apart from the above prior arts (1) to (5), (6) heat-resistant fibers such as aromatic polyamide fibers and aromatic polyamideimide fibers having a melting point of about 400 ° C .;
Proposal of cushioning material for forming press, which consists of heat-resistant fibers such as phenol fibers, polyamide fibers, and polyester fibers as the main fibers, mixed with binder fibers and made into paper, and laminated by heating and pressing. (Japanese Unexamined Patent Publication (Kokai) No. 3-119198), the prior art of (6) describes that a core-sheath fiber is used as the binder fiber. However, this (6)
The prior art is used when pressing and manufacturing a flat plate-like body such as a synthetic resin laminated decorative board or an electrical insulating board, and interposed between a flat press board and a flat material to be pressed. Since the present invention relates to a cushion material and does not per se relate to a press-formed paper used for a press-formed product having a squeeze, no consideration is given to stretchability during press-forming. In addition, in the prior art of (6), natural pulp is not used, and from this point, an attempt to manufacture a molded article such as a container by press molding using natural pulp is the technical content. Are very different.

Therefore, proposals for manufacturing molded articles such as containers by press-molding paper as it is, without using wet papermaking molding using a mesh mold, have been proposed in the above-mentioned prior arts (1) to (5). As can be seen, various processes have been conventionally performed, but the process is simple, with good thermal efficiency, and does not cause breakage of the paper during press forming.
mm, and press-forming paper capable of producing deep drawn products having complex irregularities, and press-forming technology using such paper has not yet been put to practical use. .

[0013]

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a paper having a depth of up to 50 mm and having complicated irregularities even when press-formed in a dry state without wetting the paper. To provide a press-formed paper mainly composed of natural pulp, which can smoothly produce a deep drawn product even in a simple process with good thermal efficiency without causing breakage of the paper. It is. The object of the present invention is to use a paper mainly composed of natural pulp, press-mold the paper in a dry state without wetting, and form a deep-drawn container or the like with a simple process and a good process. An object of the present invention is to provide a method that can be manufactured smoothly with thermal efficiency. It is a further object of the present invention to provide a press-formed article made of paper mainly composed of natural pulp.

[0014]

Means for Solving the Problems In order to achieve the above-mentioned object, the present inventors have conducted various studies on paper suitable for press molding from the viewpoint of its material and from the viewpoint of press molding technology. As a result, when a press-formed paper is produced using natural pulp and a thermoplastic polymer fiber having a heat-adhesive property and a specific elongation at a press forming temperature in a specific ratio, the resulting paper is as follows. It has very good stretchability and good strength at the time of press molding, and it does not break even when pressed as it is in a dry state, for example, a depth such as 50 mm in depth and having complex irregularities It has been found that a drawn molded product can be manufactured smoothly. In addition, in performing press molding using the paper, the present inventors may perform press molding using only one sheet of paper, but perform press molding in a state where two or more sheets of paper are stacked. The present inventors have found that forming a molded product by the above method makes it possible to produce the above-described deep-drawn molded product more smoothly, and completed the present invention based on those findings.

That is, the present invention relates to a press-formed paper containing natural pulp and thermoplastic polymer fiber, wherein the content ratio of natural pulp: thermoplastic polymer fiber in the press-formed paper is 99: 1 to 50:50 ( (Weight ratio), and a thermoplastic polymer fiber having thermal adhesion at a press molding temperature and a fiber elongation of 20 to 70% was used as the thermoplastic polymer fiber. Press-formed paper.

Further, the present invention is a press-formed paper containing natural pulp and thermoplastic polymer fiber, wherein the content ratio of natural pulp: thermoplastic polymer fiber in the press-formed paper is 99: 1 to 50:50 ( Weight ratio), and as the thermoplastic polymer fiber, has thermal adhesiveness at a press molding temperature, a fiber elongation of 20 to 70%, and a shrinkage factor of 15 minutes at 140 ° C. A press-formed paper using a thermoplastic polymer fiber of 20% or more.

Further, the present invention is a method for producing a molded article, characterized by carrying out heat press molding using the above-mentioned press molded paper, and as a preferred embodiment of such a press molding method, The method includes a method in which two or more formed sheets are stacked and press-formed at a temperature and pressure at which the stacked press-formed sheets are laminated and integrated. The present invention also includes a press-formed product manufactured by the above method.

[0018]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail. The press-formed paper of the present invention is mainly composed of natural pulp and thermoplastic polymer fibers. In this case, the type of natural pulp is not particularly limited, and any natural pulp can be used. Examples of the natural pulp used in the press-formed paper of the present invention include hardwood wood pulp, softwood wood pulp, esparto pulp, Manila hemp pulp,
Sisal pulp, linter pulp and the like can be mentioned. The natural pulp may be subjected to a treatment such as mercerization. The above-mentioned natural pulp may be used alone or in combination of two or more. Further, the natural pulp may be virgin pulp, used waste paper pulp, or a combination of virgin pulp and waste paper pulp. When waste paper pulp is used, for example, those having a long fiber length obtained from milk packs, diaper waste materials, wrapping paper and the like are preferably used. From the point that paper tearing is less likely to occur during press molding,
The natural pulp used for the press-formed paper preferably has a fiber length of about 1 mm or more, more preferably about 1.5 to 6 mm, and further preferably about 2 to 3 mm.

In the press-formed paper of the present invention, it is necessary that the thermoplastic polymer fiber used together with the natural pulp has a thermal adhesive property at the press-forming temperature. The use of thermoplastic polymer fibers that do not have thermal adhesion at the press forming temperature allows the resulting paper to be bonded to natural pulp and to be bonded to the natural pulp and thermoplastic resin, even if pressed under heating. Bonding with the united fiber, since the bonding between the thermoplastic polymer fibers is not performed by the thermoplastic polymer fiber, it is not possible to impart strength or stretchability that can withstand press molding to paper, and a molded product with a draw, particularly A deep drawn molded product having a depth of 50 mm and having complex irregularities cannot be manufactured smoothly without breakage or the like. Here, in the present invention, “has thermal adhesiveness at press molding temperature”
Means that at the heating temperature during press molding, the thermoplastic polymer fibers soften or melt and adhere to the natural pulp, and the thermoplastic polymer fibers adhere to each other to form natural pulp or thermoplastic polymer that constitutes paper It means joining between the fibers and improving the stretchability and strength of the paper.

Although not particularly limited, generally, when the press-formed paper of the present invention is used, it is preferably 100
Since the press molding is performed at a temperature of ~ 250 ° C, the thermoplastic polymer fiber used in the press molded paper of the present invention has a
It is preferred that at least a part or all of the surface of the fiber softens or melts at a temperature of ~ 250 ° C. As will be described later, the press-formed paper of the present invention is usually produced by wet-making papermaking raw material containing natural pulp and thermoplastic polymer fibers and then drying the paper. ~ 140 ° C)
It is more preferable that the resin can be softened by the above method and can adhere to natural pulp.

Further, in the press-formed paper of the present invention, the thermoplastic polymer fiber used with natural pulp has an elongation of 20%.
It needs to be 70%, and preferably 30% to 60%. If a thermoplastic polymer fiber having a fiber elongation outside the range of 20 to 70% is used, the press-formed paper does not have sufficient stretchability and strength to withstand the press-forming, and the paper breaks at the time of press-forming to form. A product, especially a deep drawn product cannot be manufactured smoothly. In particular, when the fiber elongation of the thermoplastic polymer fiber is less than 20%, the molded article is likely to be torn at corners and the like, while the fiber elongation is 70%.
%, No strength is given to the press-formed paper, and in any case, the press-forming is not performed smoothly. In addition,
The fiber elongation of the thermoplastic polymer fiber referred to in this specification is J
It refers to the value measured by IS-L-1015.

Further, the thermoplastic polymer fiber used for the press-formed paper of the present invention has a shrinkage rate when held at 140 ° C. for 15 minutes [hereinafter referred to as “shrinkage rate (140 ° C./15
Min) is preferably 20% or more ", since a press-formed paper having excellent press-formability is obtained, and the shrinkage ratio (140 ° C / 15
Min) is more preferably 50 to 90%. here,
The "shrinkage ratio (140
° C / 15 minutes) "means 0.05 m of thermoplastic polymer fiber
It refers to the shrinkage ratio with respect to the fiber length before heating when heated and held at 140 ° C. for 15 minutes under a load of g / d.

In the present invention, as the thermoplastic polymer fiber constituting the press-formed paper, any fiber made of a thermoplastic polymer satisfying the above requirement that the fiber elongation is 20 to 70% can be used. The type of the thermoplastic polymer forming the fiber, the shape of the fiber and the presence or absence of the composite are not particularly limited. The cross-sectional shape of the thermoplastic polymer fiber may be any of circular, irregular, hollow, and the like. Also,
The thermoplastic polymer fiber may be a fiber composed of only one kind of thermoplastic polymer, or a composite fiber or a mixed fiber obtained by compounding or mixing two or more kinds of thermoplastic polymers. In this case, the core-sheath type composite fiber, the sea-island type composite fiber, or the side-by-side type composite fiber may be used.

Among them, the thermoplastic polymer fibers constituting the press-formed paper are softened or melted at the temperature at the time of press molding, and the sheath made of a low melting point thermoplastic polymer is softened or melted at the temperature at the time of press molding. When the core-sheath type conjugate fiber is composed of a core made of a thermoplastic polymer having a high melting point, the sheath having a low melting point is softened or melted by heat at the time of press molding to join the natural pulp and the natural pulp. Bonding with thermoplastic polymer fibers, high stretchability and strength that can withstand deep drawing etc. are imparted to press-formed paper by providing bonding between thermoplastic polymer fibers, and are softened or softened by heat during press forming. The high melting point core that does not melt retains the fiber strength and imparts higher strength and stiffness to the press-formed paper, so that a press-formed paper having more excellent press-formability can be obtained. In preferred. In this case, the ratio of the sheath part to the core part in the core-sheath type conjugate fiber is generally set to about 30:70 to 70:30 by weight, from the viewpoint of obtaining press-formed paper excellent in press formability. More preferably, it is more preferably 40:60 to 60:40.

The thermoplastic polymer fibers preferably used in the press-formed paper of the present invention include, for example, polyethylene terephthalate fiber; polybutylene terephthalate fiber; modified polyethylene terephthalate fiber; modified polybutylene terephthalate fiber; modified polypropylene fiber;
And a core-in-sheath composite fiber comprising a sheath made of at least one of modified polyethylene terephthalate, modified polybutylene terephthalate, polyethylene and modified polypropylene and a core made of at least one of polyethylene terephthalate, polybutylene terephthalate, polypropylene and polyamide. These thermoplastic fibers may be used alone or in combination of two or more. In particular, if the thermoplastic polymer fiber is a fiber made of an amorphous thermoplastic polymer, its application range is wide, so even if there is a difference in the temperature of the mold during press molding, a desired molded product can be produced. It is preferable because it can be obtained smoothly.

Here, the above-mentioned "modified polyethylene terephthalate" means, in addition to the main structural units ethylene glycol unit and terephthalic acid unit, isophthalic acid unit, phthalic acid unit, 2,3-naphthalene dicarboxylic acid unit, 5- Aliphatic dicarboxylic acid units such as aromatic dicarboxylic acid units such as alkali metal sulfoisophthalic acid units, adipic acid units, azelaic acid units, and sebacic acid units; diols such as diethylene glycol units, propylene glycol units, and 1,4-butanediol units It refers to an ethylene terephthalate-based polymer containing a small amount of units and the like (usually 25 mol% or less), and among them, an amorphous ethylene terephthalate-based polymer is particularly preferable. Also,
The “modified polybutylene terephthalate” referred to above is
Aromatic dicarboxylic acid units such as isophthalic acid units, phthalic acid units, 2,3-naphthalene dicarboxylic acid units, and 5-alkali metal sulfoisophthalic acid units together with the main structural units of 1,4-butanediol unit and terephthalic acid unit , Adipic acid units, azelaic acid units, sebacic acid units and other aliphatic dicarboxylic acid units; ethylene glycol units, diethylene glycol units, propylene glycol units and other diol units in small amounts (usually 2
(5 mol% or less). Among them, an amorphous butylene terephthalate polymer is particularly preferable. Further, "modified polypropylene" refers to a propylene-based polymer containing a small amount (usually 30 mol% or less) of ethylene units and unsaturated carboxylic acid units (for example, maleic acid units) together with propylene units, which are main structural units, Amorphous ones are preferred.

In the press-formed paper of the present invention, among the above-mentioned thermoplastic polymer fibers, modified polyethylene terephthalate containing isophthalic acid units in a proportion of 20 to 60 mol% with respect to the total acid component has a fiber cross-sectional periphery. 40% by rate
By using a core-sheath type composite fiber having a non-copolymerized polyester containing in the above ratio, particularly a sheath made of such an amorphous polyester copolymer and a core made of polyethylene terephthalate, press molding is performed. At the time, the adhesion between the fibers, the adhesion between the fibers and the natural pulp are performed well, and the press molding can be performed extremely smoothly. For example, a deep drawing having a depth of 50 mm or more and having complex irregularities Even a molded product can be easily manufactured.

The above-mentioned amorphous polyester copolymer fibers include, for example, (i) 40 mol% or more of terephthalic acid units, 20 to 60 mol% of isophthalic acid units, and 75 mol% of ethylene glycol units. (Ii) the total proportion of aromatic copolymer units other than terephthalic acid units and isophthalic acid units and aliphatic and / or alicyclic copolymer units other than ethylene glycol units Is from 0 to 25 mol% based on all the acid component units in the copolymerized polyester; (iii) the proportion of the aliphatic and / or alicyclic copolymerized units other than the ethylene glycol unit is such that the unit raw material is [ C
Not more than 25% by weight, based on the weight of the copolymerized polyester when it is of the [OH] and / or [OH] type; and (iv)

[0029]

2.83 ≦ log η ₀ ≦ 6.10 5.0 (1 + log [η]) + 0.30 ≦ log η ₀ ≦ 5.0 (1 + log [η]) + 1.30 0.45 ≦ 1 + log [η] ≦ 1.0 [where η ₀ is The melt viscosity (poise) of the copolyester under zero shear stress at 160 ° C., [η] indicates the intrinsic viscosity (dl / g) of the copolyester] and the melt viscosity η ₀ and the intrinsic viscosity [η] A copolymerized polyester fiber in which the non-crystalline copolyester component occupies 40% or more in fiber cross-sectional area ratio. The details of the above-mentioned copolymerized polyester fiber are as described in JP-A-58-136828.

The above-mentioned thermoplastic polymer fibers used in the press-formed paper of the present invention can be obtained by melt-spinning the above-mentioned thermoplastic polymer by a conventional method. If the fiber elongation of the thermoplastic polymer fiber does not satisfy the above-mentioned range of the present invention depending on the melt spinning conditions and the like, the spinning conditions during melt spinning, stretching conditions, heat treatment conditions and the like should be changed or adjusted. The fiber elongation can be in the range of 20 to 70% depending on the temperature, and if necessary, the shrinkage (140 ° C./15 minutes)
Can be set to 20% or more.

In the present invention, the tensile strength of the thermoplastic polymer fiber used for the press-formed paper is preferably 3 g / d or more, but is not limited thereto.
It is more preferably g / d or more, and in that case, a press-formed paper which is more excellent in press-forming that can sufficiently withstand deep drawing press-forming and the like can be obtained.

Further, in the press-formed paper of the present invention, since the single fiber fineness of the natural pulp used with the thermoplastic polymer fiber is usually about 0.5 to 30 denier,
In order to improve the balance with natural pulp so that the natural pulp and thermoplastic polymer fibers are evenly dispersed during papermaking, it also provides strength to press-formed paper and has good adhesive action during press-forming. In order to achieve the above, the single fiber fineness of the thermoplastic polymer fiber is preferably about 0.5 to 5.0 denier, and more preferably about 1.0 to 3.0 denier. The single fiber fineness of the thermoplastic polymer fiber is 0.
If it is less than 5 denier, the strength of the press-formed paper is particularly reduced and tearing is likely to occur during press molding. On the other hand, if it exceeds 5.0 denier, the function of the thermoplastic polymer fiber as an adhesive decreases. Bonding of natural pulp is not performed, and it becomes difficult to obtain paper having stretchability and strength suitable for press molding.

In the press-formed paper of the present invention, the natural pulp and the thermoplastic polymer fiber are uniformly dispersed at the time of papermaking, and the obtained press-formed paper is provided with good stretchability and strength. It is preferable to use a thermoplastic polymer fiber having a fiber length of about 1 to 20 mm,
It is more preferred to use one of about 2 to 7 mm. If the fiber length of the thermoplastic polymer fiber is less than 1 mm, it is difficult to obtain a press-formed paper having stretchability and strength that can withstand press molding, while if it exceeds 20 mm, the dispersibility of the papermaking becomes poor and the heat becomes poor. Paper in which the plastic polymer fibers are uniformly dispersed becomes difficult to obtain, and the quality of the paper tends to be non-uniform.

The press-formed paper of the present invention is obtained by combining the above-mentioned natural pulp and the above-mentioned thermoplastic polymer fiber with natural pulp: thermoplastic polymer fiber = 99: 1 to 50:50.
(Weight ratio), it is necessary to include the
It is preferable to include 70:30 (weight ratio). When the proportion of the thermoplastic polymer fiber is less than 1% by weight based on the total weight of the natural pulp and the thermoplastic polymer fiber, the adhesive function of the thermoplastic polymer fiber is not provided, and the stretchability and strength are excellent. Paper cannot be obtained and tears occur during press molding, and it is not possible to obtain a deep-drawn molded product particularly having a depth of up to 50 mm. On the other hand, if the proportion of the thermoplastic polymer fiber exceeds 50% by weight based on the total weight of the natural pulp and the thermoplastic polymer fiber, the shrinkage of the paper during press molding becomes too large, and the resulting press-formed product Is liable to become unstable, and this does not meet the object of the present invention for producing a paper container or the like using as little polymer as possible. In particular, in the press-formed paper of the present invention, the content of the thermoplastic polymer fiber is adjusted to 1 to 7 based on the total weight of the natural pulp and the thermoplastic polymer fiber.
In the case of a small amount of about% by weight, a molded article such as a container manufactured from the press-molded paper of the present invention is recovered after use, put in water or the like, and stirred, so that natural pulp can be easily recovered. You can use it again.

The press-formed paper of the present invention containing the above-mentioned natural pulp and thermoplastic polymer fiber in the above-mentioned ratio has good stretchability and strength at the time of press-forming itself, and is a deep-drawn molded product. Can also be manufactured smoothly. However, in some cases, fineness and wrinkles (crepes), corrugations and other irregularities may be provided, in which case the stretchability of the paper during press molding can be further improved. . At this time, the unevenness such as crepe and corrugation may be applied in a wet state at the time of paper making or after drying. In addition, irregularities such as crepe and corrugation are provided in a direction parallel to the paper length direction, a direction perpendicular to the paper length direction (width direction), a direction oblique to the paper length direction, Any combination of the directions may be used, and may be determined according to the shape and structure of the press-formed product to be manufactured.

The press-formed paper of the present invention may be used together with the above-described natural pulp and thermoplastic polymer fiber, if necessary, in a range not interfering with the object of the present invention. Enhancer, wet strength enhancer,
It may contain additives such as a water repellent and a waterproofing agent, and fibers other than the above-mentioned thermoplastic polymer fibers. If necessary, the surface of the press-formed paper may be subjected to a treatment such as lamination as long as it does not hinder the hot press-forming.

In the press-formed paper of the present invention, the basis weight of one sheet of paper is 10 to 40 in view of processability in paper production, press-formability of paper, handleability in press-forming, and the like.
It is preferably set to about 0 g / m ² ,
g / m ² , more preferably 50 to 200 g
/ M ² is more preferable. Further, in the press-formed paper of the present invention, in order to further improve the press-formability of the press-formed paper, at least one of the longitudinal elongation and the lateral elongation of the paper is set to 20% or more. It is preferable to keep it. Further, in the press-formed paper of the present invention,
The tensile strength in at least one of the longitudinal and transverse directions of the paper is preferably set to 1.5 kgf or more, more preferably 2 kgf or more. Further, the dimensions of the press-formed paper of the present invention are not particularly limited, and may be set to a size suitable for manufacturing a target press-formed product.

The production method and production conditions of the press-formed paper of the present invention are not particularly limited, and the press-formed paper can be produced by employing a conventionally known papermaking method using natural pulp and papermaking conditions. Although not limited, the press-formed paper of the present invention is, for example, a pulp, beater, disintegrating the papermaking raw material using a refiner or the like to prepare a slurry containing natural pulp and thermoplastic polymer fibers, this slurry One or two types of papermaking nets such as circular nets, short nets, long nets, etc.
Wet paper making is performed by using more than one seed to form wet paper, and it is dried at a temperature of generally 100 to 140 ° C. using a drying machine such as a Yankee dryer or a multi-cylinder dryer, and wound up. Can be manufactured. At this time, in the case where the press-formed paper of the present invention is provided with the irregularities such as the crepe and the corrugation described above, an appropriate method (for example, a drier for drying the wet paper when drying the wet paper) is used. The introduction speed of the is faster than the removal speed from the dryer,
A method using a corrugated embossing roll) may be used to provide the unevenness.

When press-forming using the press-formed paper of the present invention, one press
Press molding may be performed as it is using two pieces of press-formed paper, or press-forming may be performed by stacking two or more press-formed papers. Of these, the basis weight of one press-formed sheet is kept as thin as possible within the range of 10 to 400 g / m ² described above, and two or more sheets, preferably about 3 to 40 sheets, are stacked, and heated under heating. When press forming is performed while pressing and forming, the stacked papers are joined and integrated together, the respective papers are formed, joined, laminated and integrated while stretching well during the press forming, forming a deep drawing A product, for example, a deep drawn product having a depth of up to 50 mm is particularly preferable because it can be manufactured extremely smoothly without causing breakage or the like at its corners.

The molding apparatus used for press molding is not particularly limited, and for example, a press mold composed of a male mold and a female mold can be used as in the conventional press molding. The temperature at the time of press molding is a temperature of 100 to 250 ° C. from the viewpoint of preventing deterioration of natural pulp, thermal efficiency, press moldability, and performing press molding while maintaining good stretchability and strength of press molded paper. Preferably 110
Preferably it is at a temperature of ~ 180 ° C. As a heating method at that time, even if only the press molding die is heated without preheating the press molding paper, both the press molding die and the press molding die are heated in advance. Alternatively, in some cases, only the press-formed paper may be heated in advance, and then the press-formed paper may be pressed by an unheated press-forming die. Among them,
The method of heating only the press molding die is preferred from the viewpoint of processability. The heating method is not particularly limited, and for example, a heating method using an electric heater, a hot air heating method, a steam heating method, a heating oil circulation method, a combination of these methods, and the like can be adopted. However, electric heating is preferable in terms of simplicity.

Also, the press pressure and the like are determined by the press-formed paper.
The type and amount of the thermoplastic polymer fiber used in
Size, thickness, and press-formed paper to overlap
Can be adjusted according to the number of
5 to 500 kg / cm^Two Press pressure of about
Can manufacture molded articles without damaging the paper.
10 to 300 kg / cm^Twoof
Pressing pressure is more preferable, 20 to 200 kg / cm^Two
Is more preferable. Also, press molding time
The size and thickness of the target molded product,
The number of less forming papers, the heat used in press forming paper
Although it can be adjusted according to the type and amount of the plastic polymer fiber,
In general, when performing at the above temperature at the above press pressure
Also, it is preferable to keep the press time about 2 to 20 seconds.
New

The shape, structure, size, thickness and the like of the molded product produced by the above-mentioned press molding are not particularly limited, and can be appropriately determined according to the use and purpose of use of the molded product. In general, when the required number of the above-described press-formed papers of the present invention are stacked and press-formed by setting the thickness of the container wall of the press-formed product of the present invention to about 0.5 to 1.5 mm, a good A high-quality molded product having shape retention, high strength, cushioning properties, and the like can be obtained.

The press-formed product of the present invention can be used as a packaging container for electric / electronic parts and other industrial parts, a buffering container, a tray and a barrel, other various food packaging containers, a paper plate, a paper cup and the like. Press molding of expanded polystyrene sheet,
It can be effectively used in place of plastic molded articles such as molded articles formed by molding using expanded polystyrene beads and molded articles using polyvinyl chloride sheets and foams.

[0044]

EXAMPLES The present invention will be specifically described below by way of examples, but the present invention is not limited thereto. In the following examples, the fiber elongation, shrinkage (140 ° C./15 minutes), tensile strength, and elastic modulus of the thermoplastic polymer fiber were determined as follows.

Fiber elongation of thermoplastic polymer fiber : JIS-
It measured according to L-1075.

The shrinkage of the thermoplastic polymer fiber (140 ° C. /
15 ° C.) : A sample of 450 mm in length is randomly sampled from a plurality of thermoplastic polymer fibers (filaments) before cutting into short fibers, and a load of 0.05 mg / d is applied to each of the samples. After heating for 15 minutes in an atmosphere at a temperature of 140 ° C., the sample was taken out, taken out, and the length (L ₁₅ ) (mm) after heating for each use was measured. The shrinkage ratio of the thermoplastic polymer fiber was calculated by the following equation. (140 ° C / 15 minutes)
The average value of 10 samples was taken.

[0047]

## EQU3 ## Shrinkage rate of thermoplastic polymer fiber (140 ° C./15 minutes) (%)
= {(L ₀ −L ₁₅ ) / L ₀ } × 100 [where L ₀ = length of sample before heating (450 m
m), length of sample after heating at L ₁₅ = 140 ° C. for 15 minutes (mm)]

Tensile strength of thermoplastic polymer fiber : JIS-
It measured according to L-1075.

Example 1 (1) Modified polyethylene terephthalate having an isophthalic acid unit at a ratio of 45 mol% as a sheath, and polyethylene terephthalate as a core, sheath: core =
The core-in-sheath type conjugate fiber was manufactured in a weight ratio of 50:50. As a result, the obtained core-sheath type conjugate fiber has a sheath portion having no melting point but softening at 110 ° C., a single fiber fineness of 2 denier, a fiber elongation of 35%, and a shrinkage rate (140 ° C. /
(15 minutes) was 82% and the tensile strength was 4.5 g / d. This core-sheath type composite fiber has a fiber length of 5 m.
m. (2) Using 5 parts by weight of a core-sheath type composite fiber having a fiber length of 5 mm obtained in the above (1) and 95 parts by weight of waste paper pulp (average fiber length 2.5 mm) extracted from diaper waste material, and water was added thereto. In addition, the mixture was mixed with a pulper to prepare a stock solution having a total concentration of the waste paper pulp and the core-sheath type composite fiber of 0.5% by weight. Wet paper is made, creped with a doctor attached to a press roll, and then passed through a Yankee dryer and then a multi-cylinder dryer, while keeping the drying temperature of the above two types of dryers within the range of 110 ° C. Thus, a press-formed paper having a crepe with a basis weight of 200 g / m ² was produced. (3) Six press-formed sheets obtained in the above (2) are piled up, and the temperature of the male mold and the temperature of the female mold are both 150 ° C., and the pressing pressure is 100 kg / cm ² using a heating press. Perform hot press molding for 3 seconds.
A press-formed product having a rectangular parallelepiped concave portion of width x depth = 50 mm x 30 mm x 20 mm was manufactured. The resulting press-formed product has an average wall thickness of 0.9 m.
m, no breaks occurred at the four corners at the bottom and other parts, and the four corners were not thin, resulting in a good finish.

Example 2 (1) Modified polyethylene terephthalate having an isophthalic acid unit at a ratio of 36 mol% as a sheath, and polyethylene terephthalate as a core, sheath: core =
The core-in-sheath type conjugate fiber was manufactured in a weight ratio of 50:50. As a result, the obtained core-sheath type conjugate fiber has a sheath portion having no melting point but softening at 110 ° C., a single fiber fineness of 2 denier, a fiber elongation of 50%, and a shrinkage ratio (140 ° C. /
(15 minutes) was 50% and the tensile strength was 4.0 g / d. This core-sheath type composite fiber has a fiber length of 5 m.
m. (2) Example 1 using 3 parts by weight of the core-in-sheath composite fiber having a fiber length of 5 mm obtained in the above (1) and 97 parts by weight of waste paper pulp (average fiber length 2.5 mm) extracted from diaper waste material. Press-formed paper having a crepe with a basis weight of 100 g / m ² was produced in the same manner as in (2) above, and press-formed using the same in the same manner as (3) in Example 1. As a result, the obtained press-formed product did not have any tears at the four corners at the bottom and other parts, and the four corners were not thin, resulting in a good finish. Was.

Example 3 (1) A modified polypropylene having an ethylene unit at a ratio of 10 mol% is used as a sheath, and a polypropylene is used as a core so that the sheath: core = 50: 50 weight ratio. A core-sheath composite fiber was manufactured. As a result, the obtained core-sheath type composite fiber had a melting point of the sheath portion of 140 ° C., a single fiber fineness of 2 denier, a fiber elongation of 48%, and a shrinkage ratio (1%).
(40 ° C./15 minutes) 29% and a tensile strength of 6.5 g /
d) was a core-sheath type composite fiber. This core-sheath type composite fiber was cut into a fiber length of 5 mm. (2) Example 1 using 5 parts by weight of a core-sheath type composite fiber having a fiber length of 5 mm obtained in the above (1) and 95 parts by weight of waste paper pulp (average fiber length 2.5 mm) extracted from diaper waste material. Press-formed paper having a crepe with a basis weight of 100 g / m ² was produced in the same manner as in (2) above, and press-formed using the same in the same manner as (3) in Example 1. As a result, a press-formed product having an average thickness of 0.9 mm in the wall portion was obtained, no breaks occurred at the four corners at the bottom and other portions, and the four corners were thin. It was not finished and had a good finish.

Example 4 (1) Polypropylene was spun alone and the melting point was 17
A polypropylene fiber having a denier of 0 ° C., a fineness of a single fiber of 2 deniers, a fiber elongation of 49%, a shrinkage ratio (140 ° C./15 minutes) of 12%, and a tensile strength of 4.4 g / d was obtained. This polypropylene fiber was cut into a fiber length of 5 mm. (2) Using 5 parts by weight of the polypropylene fiber having a fiber length of 5 mm obtained in the above (1) and 95 parts by weight of waste paper pulp (average fiber length of 2.5 mm) extracted from diaper waste material, the procedure of (2) of Example 1 was used. A press-formed paper having a crepe with a basis weight of 100 g / m ² was produced in the same manner as in (1), and press-formed using the same in the same manner as in (3) of Example 1. As a result, a press-formed product having an average wall thickness of 0.9 mm was obtained. The four corners at the bottom were almost intact without tearing, but the two corners were slightly thinner.

Comparative Example 1 (1) Polyethylene terephthalate was spun alone and had a softening point of about 90 ° C., a single fiber fineness of 2 denier, a fiber elongation of 257%, and a shrinkage rate (140 ° C./15 minutes). Is 60%
And a polyethylene terephthalate fiber having a tensile strength of 1.7 g / d was obtained. This polyethylene terephthalate fiber was cut into a fiber length of 5 mm. (2) Using 5 parts by weight of the polyethylene terephthalate fiber having a fiber length of 5 mm obtained in the above (1) and 95 parts by weight of waste paper pulp (average fiber length of 2.5 mm) extracted from diaper waste material, 100 in the same way as 2)
g / m ² of press-formed paper having a crepe,
Press molding was carried out in the same manner as in (3) of Example 1 using this. As a result, two of the four corners at the bottom of the press-formed product were torn, resulting in a poor finish.

[0054]

When the press-formed paper of the present invention is used, a press-formed product having a desired shape and dimensions can be produced extremely smoothly without causing breakage of the paper during press-forming. Further, it is possible to smoothly produce a deep-drawn press-formed product having a depth of 50 mm, which is impossible with conventional press-forming of paper, and having complicated irregularities. In particular, when performing heat press molding in a state where a plurality of the press-formed papers of the present invention are stacked, it is possible to produce the above-described deep-drawn molded article extremely smoothly without causing breakage of the paper or the like. . And, when the press-formed paper of the present invention is used, the press-forming can be performed in a dry state without being wetted before or during the press-forming, so that the press-forming process is extremely simple, Moreover, since it is not necessary to dry the wet paper, it is advantageous in terms of thermal efficiency. Since the press-formed product obtained by the present invention has good strength and buffering action, it is used for packaging containers for electric and electronic parts, packaging containers for other industrial parts, packaging containers for various foods, paper cups, paper plates. It can be effectively used for various applications such as. The press-formed product such as the packaging container of the present invention has a greatly reduced use ratio of plastics as compared with conventional plastic packaging containers, and therefore reduces various adverse effects that have been caused in used plastics. Or can be eliminated.

 ──────────────────────────────────────────────────続 き Continuing from the front page (72) Inventor Kimiaki Shimoyama 5-7-7 Nyorin-cho, Kasugai-shi, Aichi Japan Inside Hi-Pack Co., Ltd. 899-1 Inside Japan Frepa Co., Ltd. (72) Inventor Hideo Hayashi 1-12-13 Umeda, Kita-ku, Osaka-shi, Osaka Kuraray Co., Ltd.

Claims (12)

[Claims] 1. A press-formed paper containing natural pulp and thermoplastic polymer fibers, wherein the content ratio of natural pulp: thermoplastic polymer fibers in the press-formed paper is 99: 1-5.
0:50 (weight ratio), and as the thermoplastic polymer fiber, a thermoplastic polymer fiber having thermal adhesion at a press molding temperature and a fiber elongation of 20 to 70% was used. Press formed paper characterized by the above. 2. Press-formed paper containing natural pulp and thermoplastic polymer fiber, wherein the content ratio of natural pulp: thermoplastic polymer fiber in the press-formed paper is 99: 1-5.
0:50 (weight ratio), and as the above-mentioned thermoplastic polymer fiber, has thermal adhesion at a press molding temperature, a fiber elongation of 20 to 70%, and 15 ° C at 140 ° C.
Press-formed paper using a thermoplastic polymer fiber having a shrinkage factor of 20% or more when held for one minute. 3. The press-formed paper according to claim 1, wherein the thermoplastic polymer fiber is a thermoplastic polymer fiber whose surface is at least partially softened at a papermaking temperature. 4. The thermoplastic polymer fiber according to claim 1, wherein at least a part of the surface of the thermoplastic polymer fiber is a thermoplastic polymer fiber that is softened or melted at a temperature during press molding.
Press-formed paper. 5. The thermoplastic polymer fiber has a surface portion having a softening point or melting point of 80 to 250 ° C.
Press-formed paper according to any one of the above. 6. A sheath made of a low-melting thermoplastic polymer whose thermoplastic polymer fiber is softened or melted at the temperature during press molding, and a high-melting thermoplastic that is not softened or melted at the temperature during press molding. The press-formed paper according to any one of claims 1 to 5, wherein the press-formed paper is a core-sheath composite fiber comprising a polymer core. 7. The thermoplastic polymer fiber is a polyethylene terephthalate fiber; a polybutylene terephthalate fiber;
A modified polyethylene terephthalate fiber; a modified polybutylene terephthalate fiber; a modified polypropylene fiber; and a sheath made of at least one of modified polyethylene terephthalate, modified polybutylene terephthalate, polyethylene and modified polypropylene, and at least polyethylene terephthalate, polybutylene terephthalate, polypropylene and polyamide. The press-formed paper according to claim 6, wherein the press-formed paper is at least one kind of thermoplastic polymer fiber selected from a core-sheath type conjugate fiber having one kind of core. 8. A thermoplastic polyester fiber comprising: (i) a copolymer polyester having a terephthalic acid unit of 40 mol% or more, an isophthalic acid unit of 20 to 60 mol%, and an ethylene glycol unit of 75 mol% or more. (Ii) the total proportion of aromatic copolymer units other than terephthalic acid units and isophthalic acid units and aliphatic and / or alicyclic copolymer units other than ethylene glycol units is equal to the total acid in the copolymerized polyester. (Iii) the ratio of the aliphatic and / or alicyclic copolymer units other than the ethylene glycol unit is [C]
Not more than 25% by weight based on the weight of the above-mentioned copolymerized polyester when it is of the [OH] and / or [OH] type; and (iv) the following formula: 2.83 ≦ logη ₀ ≦ 6.10 5.0 (1 + log [η]) + 0.30 ≦ logη ₀ ≦ 5.0 (1 + log [η]) + 1.30 0.45 ≦ 1 + log [η] ≦ 1.0 [wherein η ₀ is copolymerization at 160 ° C. under zero shear stress. the melt viscosity of the polyester (poise), [eta] is intrinsic viscosity (dl / g) having a melt viscosity eta ₀ and intrinsic viscosity satisfying [eta] a is shown on the copolyester; non-crystalline copolymerized polyester component 8. A copolyester fiber occupying 40% or more in fiber cross-sectional circumference.
Press-formed paper. 9. The press-formed paper according to claim 1, having a basis weight of 10 to 400 g / m ² . 10. A method for producing a molded product, wherein hot press molding is performed using the press molded paper according to any one of claims 1 to 9. 11. The hot press forming is performed by stacking two or more press-formed papers according to any one of claims 1 to 9 under a temperature and a pressure at which the stacked press-formed papers are laminated and integrated. Method for manufacturing molded articles. 12. A press-formed product manufactured by the method according to claim 10.