JPH0129697B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a flocked product that is breathable, has a high volume, and has excellent recovery elasticity. In conventional flocked products, the adhesive layer that adheres short fibers to the base material is formed of a continuous thin coating layer, which not only lacks breathability but also lacks volume. Even if a base material was used, its stretchability could not be fully demonstrated. Therefore, in order to eliminate these drawbacks, for example, foamed vinyl chloride leather (with knitted back surface) has been used as the base material, or flannel, which has a voluminous feel, or double knit, etc., have been used as the base material. However, these methods had advantages and disadvantages. For example, PVC leather has many problems during dry cleaning. That is, the pile may come off because there is no good adhesive to adhere to PVC leather, or the plasticizer used in PVC leather may be extracted and the texture may become hard. Furthermore, even if flannel or double knit with a voluminous feel is used, it is difficult to obtain a flocked product with the desired soft texture. In particular, flannel or double knits with a voluminous feel are very expensive, and the final result is an expensive flocked product, which is not suitable. In addition, as a method for manufacturing air-permeable flocked products, methods of keeping the adhesive layer in a foamed state are being used, as described in Japanese Utility Model Publication No. 50-221, Japanese Patent Publication No. 53-1770, and the like. However, in this method, the conditions for the adhesive used were
According to Publication No. 221, the adhesive (emulsion) used has a solid content of 55 to 60% or more, and the expansion ratio is preferably 2 times or less. It is true that when a commercially available emulsion is foamed and used as an adhesive or a coating agent in that state, the strength is significantly reduced if the foaming ratio is increased to more than 2 times. . Furthermore, since the concentration is high and the foaming ratio is high, the surface of the foamed emulsion dries quickly, resulting in a marked decline in flocking properties. Furthermore, this method has fatal drawbacks such as the foaming ratio being less than 2 times, which results in a slightly inferior volume feeling and a lack of rebound resilience. Therefore, in order to eliminate these drawbacks, the present inventors discovered the use of foamable microspheres that foam at a relatively low temperature.Furthermore, the inventors discovered that the resin concentration of the adhesive was 55% or less and the foaming ratio was low. We have developed a method of using a foamed flocking adhesive that has excellent workability and flocking fastness even when the volume is doubled or more. However, it has been found that these two methods, foaming using microspheres and mechanical foaming using adhesive, each have the following disadvantages. That is, when using microspheres, (1) it is not possible to obtain air-permeable flocked products; (2) If a very voluminous feel or high cushioning properties are required, the amount of microspheres used must be considerably increased. Microspheres are very expensive and therefore tend to cost too much. On the other hand, in the case of mechanical foaming, (1) In order to achieve a very high foaming ratio, it is necessary to increase the gauge thickness of the doctor so that a larger amount of coating is applied than in the general case. Other coatings are difficult. (2) If the foaming ratio is lowered, coating becomes easier, but the volume and rebound properties become poorer. That's true. Therefore, the inventors of the present invention continued to conduct further studies.
As a result of intensive research into forming a more suitable hair transplant product, it was discovered that the above-mentioned drawbacks could be overcome by using microspheres in combination with mechanical foaming. That is, foamable microspheres that foam at a relatively low temperature are mixed and dispersed in the adhesive to be used, and then air is mechanically mixed with, for example, an oak mixer type or whipper type, to make the adhesive into a foamy state. Apply the desired adhesive to the base material by doctor coating or roll coating, and then flock the pile using the commonly used electrostatic flocking method.
Pre-drying at ~100℃, then heat treatment at 120-150℃ to expand the microspheres in the adhesive layer, resulting in a mixture of expanded microspheres and air-filled continuous foam voids. A flocked product with a voluminous feel and excellent breathability and rebound properties was obtained. It is thus an object of the present invention to provide an improved flocked product which not only has volume and rebound properties, but also has better air permeability. The flocked product of the present invention, which is suitable for such purpose, is a product in which short fibers are flocked on the surface of a base material through a foamed adhesive layer, and the foamed adhesive layer transfers a foamable material to a thermoplastic resin. It is formed by an expanded sphere made by heating and foaming expandable microspheres wrapped in a molecular substance, and a layer containing foam created by mechanical foaming with air, and the base end of the flocked short fiber is on the base material surface. The point is that it is fixed to the top surface of the foam adhesive layer without reaching the surface. The specific contents will be further explained in detail below. First of all, the expandable microspheres referred to in the present invention are microspheres that are made of a thermoplastic polymer encapsulating a foamable substance and are foamed at a relatively low temperature.A typical manufacturing method thereof is, for example, Although described in detail in Japanese Publication No. 42-26524, it can be easily produced by a method generally known as limited coalescence polymerization. Here, as the thermoplastic polymer constituting the foamed microspheres, polystyrene, polymethacrylic acid ester, polyvinylidene chloride, a copolymer of vinylidene chloride and acrylonitrile, a copolymer of acrylonitrile and methyl acrylate, etc. On the other hand, as foamable substances, aliphatic hydrocarbons having a boiling point below the softening point of the thermoplastic polymers, such as ethylene, propane, butene, neopentane, hexane, and heptane, are used. These thermoplastic polymers and foamable substances can be selected as appropriate depending on the adhesive used and the type of flocked product to be obtained. The most suitable materials are polyvinylidene chloride, a copolymer of vinylidene chloride and acrylonitrile, and a copolymer of acrylonitrile and methyl acrylate. However, it goes without saying that it is not limited to this. The size of the expandable microspheres is usually 1 to 50 microns in diameter before foaming, but preferably 2 to 10 microns in terms of effectiveness. These expandable microspheres are mixed into the adhesive described later and heated and foamed to promote foaming of the adhesive layer and create a foamed layer, and exist as expanded spheres in the foamed adhesive layer. It gives a sense of volume and recovery elasticity. On the other hand, in contrast to the expanded spheres, the foamed adhesive layer of the present invention further contains bubbles foamed with air, thereby imparting air permeability to the flocked product. This foam is obtained, for example, by whipping an adhesive emulsion by mechanical means, such as a foaming device, and generally has open cells. The foaming ratio when whipping this foam is 1.2 to 5 times the initial volume, preferably
It is 1.5 to 3 times. However, the expansion ratio is related to the amount of expandable microspheres added, and the amount of expandable microspheres added is 2 to 3%.
In this case, the optimal foaming ratio is 1.5 to 2.5 times. This foaming is usually performed after mixing and blending the expandable microspheres. Examples of adhesives used for flocking include synthetic rubber latex such as natural rubber latex, nitrile rubber, styrene rubber, chloroprene rubber, styrene-butadiene rubber, and nitrile-butadiene rubber, polyvinyl chloride, polyvinylidene chloride, Synthetic resin emulsions such as polyvinyl acetate, acetic acid-acrylonitrile copolymer, and polyacrylic ester are used, but the most commonly used adhesive for flocking is acrylic ester. Sometimes synthetic latexes, e.g. SBR,
NBR etc. are used together. Of course, in the present invention, any adhesive can be used as long as the resin film has some degree of elasticity, but the most suitable adhesive is an acrylic ester adhesive. Among these, the acrylic emulsion, which was developed by the present inventors and is suitable for mechanical foaming, is the most suitable. Therefore, in the hair transplantation method for obtaining the hair transplantation product according to the present invention, firstly, 0.5 to 5% of the foamable microspheres are added to the adhesive used, for example, an acrylic emulsion.
%, preferably 1-3% and stir to evenly disperse. Next, it is necessary to appropriately adjust the viscosity of the formulation, but the viscosity of acrylic emulsions generally used for hair transplantation can be adjusted freely with aqueous ammonia. In the case of the present invention,
A range of 10000-15000cps is suitable. It is also possible to use other thickeners to adjust the viscosity. In addition, it is also possible to use melamine resin (for example, product name SUMITEX M ₃ ), urea resin, epoxy resin, urethane resin, etc., which have been commonly used in the past, to further improve the strength. It is also possible to add pigments. In order to make the adhesive having such a composition and viscosity adjusted into a foamed state, it can be foamed by a known method, such as mechanical means using an oak mixer type or a whisker type. A foam stabilizer may be used in combination for the purpose of stably maintaining the foamed state of the adhesive for a long period of time, for example, 48 hours or more, at least 20 hours. Such foam stabilizers include oleic acid,
Examples include ammonium salts of higher fatty acids such as stearic acid and lauric acid, sodium lacryl sulfate, and diammonium-N-alkylsulfosuccinate. The expansion ratio of the adhesive according to the invention is 1.2 to 5 times the initial volume, preferably 1.5 to 3 times. As mentioned above, the expansion ratio is related to the amount of foamable microspheres mixed, and the optimal combination is that the amount of microspheres is 2 to 3% and the expansion ratio is 1.5 to 2.5.
It's double. Outside this range, if the amount of microspheres is small and the expansion ratio is low, the volume and rebound properties are good, but there is a problem in robustness. Next, the foamed adhesive is applied to the surface of the substrate by a known application method, such as roller coating or doctor coating. The amount of coating at that time is 50 to 200 as resin solid content.
g/m ² is suitable. Although various methods are possible for flocking the short fiber pile, an electrostatic flocking method is preferred. The substrate on which short fibers are flocked is a knitted or nonwoven fabric made of natural fibers such as cotton or rayon, or recycled cellulose fibers or synthetic fibers such as polyester or polyamide, and is breathable. The short fibers to be flocked may be any short fibers, including natural fibers such as cotton and wool, and synthetic fibers such as polyester, polyamide, and polyacrylonitrile, and the fineness and length of the fibers are determined according to the flocked product to be obtained. It is selected as appropriate depending on the use and purpose. In this way, the flocked base material as described above is dried,
The adhesive is cured while being kept in a foamed state, but the drying process in conventional hair flocking is first pre-drying at 80℃ to 100℃ for 3 to 8 minutes as the first step, then drying at 120℃ as the second step. ~160℃, generally 140~
Heat treatment at 150°C for 3 to 5 minutes. However, according to the present invention, it is preferable not to expand the microspheres during pre-drying, so pre-drying is preferably carried out at as low a temperature as possible for a short time. As for the heat treatment conditions, when the temperature is 120°C, heat treatment can be performed for up to 5 minutes, but if heat treatment is performed for more than 5 minutes, the volume will decrease. At 150℃,
Heat treatment for less than 3 minutes is most preferred. In the flocked product obtained in this way, the short fiber pile rises as the adhesive layer foams, and the short fibers float above the base material surface and are fixed by the foamed adhesive layer, giving a sense of volume that cannot be obtained with conventional flocked products. ,
It is a flocked product with rebound resilience and excellent breathability. Figure 1 of the accompanying drawings is a diagram showing an outline of the structure of the flocked product thus obtained, in which 1 is a base material, 2 is a layer deposited on the surface of the base material 1, and the material itself is The foam adhesive layer 3, which is integrally bonded to the base material 1 by the foam adhesive layer 2, has its base end fixed to the upper surface of the foam adhesive layer 2, and is spaced apart from the base material 1 surface, and is substantially attached to the foam adhesive layer 2 by the thickness of the foam adhesive layer 2. The foamed adhesive layer 2 includes expanded spheres 4 of foamable microspheres that are foamed at a relatively low temperature and that are made by wrapping the foamable substance in a thermoplastic polymer and are foamed with air. Contains foam 4 produced by mechanical foaming. The flocked product of the present invention having the above-mentioned structure has the above-mentioned excellent properties due to the presence of the foam adhesive layer, and can be used not only for materials but also for clothing. The advantages of the hair transplantation product of the present invention are listed below. (1) A flocked product that is breathable, has a voluminous feel, and is highly repellent can be obtained. (2) The amount of microspheres used can be as small as 0.5 to 5%, preferably 1 to 3%, and the mechanical expansion ratio can be easily obtained as 1.2 to 5 times, preferably 1.5 to 2.5 times. It is the magnification. (3) The adhesive used can be a commercially available emulsion with a concentration of 40 to 50%, with a concentration of 55% or less. (4) Even when using an adhesive that forms a flexible film whose secondary transition point of the adhesive resin film is -10°C or less, for example -40°C, the volume feeling and rebound resilience are maintained well. Next, the present invention will be explained in more detail with reference to Examples. Example First, foamed microspheres were manufactured by the following method. A pressure-resistant polymerization reactor equipped with a stirrer was charged with 100 parts by weight of distilled water and 15 parts by weight of 30% by weight colloidal silica dispersion water (trade name: Cataliod, manufactured by Catalyst Kagaku Kogyo Co., Ltd.). To this mixture was added 2.5 parts by weight of a 10% by weight aqueous solution of a copolymer obtained by condensation reaction from an equimolar ratio of diethanolamine and adipic acid to obtain a product having a viscosity of about 100 cps/25°C. Next, 1 part by weight of a solution containing 2.5% by weight of potassium dichromate was added,
The pH of this aqueous solution was adjusted to 4 using hydrochloric acid. An oil phase mixture was prepared using 100 parts by weight of vinylidene chloride as a monomer, 20 parts by weight of neopentane as a foaming substance, and benzoyl peroxide as a catalyst, and this was vigorously stirred with a stirring blade rotating at a speed of 10,000 rpm. The oil phase mixture was added to the water phase. The reactor is then sealed and the reaction mixture is
It was maintained at ℃ for 24 hours. During the reaction period, gentle stirring was continued, and after the reaction period was over, the temperature of the reaction mixture was lowered to near room temperature. The reaction mixture had a white appearance similar to milk. The reaction mixture was filtered and the microspheres were taken out and dried in a dryer at about 30°C. The expandable microspheres obtained were 5-8 microns. Using the thus obtained expandable microspheres, a flocked product was subsequently manufactured by the following method. That is, 82.4 parts by weight of butyl acrylate, 10 parts by weight of acrylonitrile.
1 part by weight, 36 parts by weight of acrylic acid, 4 parts by weight of N-methylolated acrylamide, and 1 part by weight of polyvinyl alcohol (degree of polymerization 500, partially modified) during polymerization.
Parts by weight were added and polymerized to produce an acrylic self-thickening and self-crosslinking emulsion. To 100 parts by weight of this emulsion (solid content concentration 45%) were added 1 part by weight of aqueous ammonia and 1.5, 2, and 3 parts by weight of the expandable microspheres produced by the above method, respectively, to prepare a dispersion. Then, use a foaming device to foam these dispersions to 1.5 to 3 times the size, and apply the foamed dispersions to the base fabric of Moss 9A in the amount applied.
Coat at 250g/ ^m2 , flock with 0.7 denier x 0.7mm rayon short fibers, pre-dry at 100℃ for 3 minutes,
Further, heat treatment was performed at 150° C. for 3 minutes to produce a flocked product of the present invention. On the other hand, for comparison, a flocked product was produced in the same manner without adding foamable microspheres, and a flocked product was produced in the same manner without foaming using a foaming device. For the flocked products of the present invention and comparative flocked products thus obtained, volume, bending resistance, rebound and air permeability were measured, and the results shown in Table 1 were obtained.

[Table] In the above table, "volume feeling" is the value measured by a thickness measuring device, and the larger the measured value, the more
It was judged that there was a feeling of volume. In addition, "bending resistance" is a value measured according to JIS L-1079 (cantilever method), and "repulsion elasticity" is a value measured by taking a sample with a width of 2 cm and a length of 15 to 20 cm from a flocked product. was bent as shown in FIG. 2, and the length L at which the bent part no longer recovered was measured, and it was determined that the larger the measured value, the better the recovery performance. As is clear from the results in Table 1 above, the comparative flocked products without the addition of expandable microspheres and without foaming using a foaming device were inferior in volume, rebound, and air permeability. In addition, flocked products in which expandable microspheres are added and foaming is not performed using a foaming device have excellent volume and rebound, but have poor air permeability. In contrast, the flocked product of the present invention was excellent in volume and rebound, and also had good air permeability.

[Brief explanation of drawings]

FIG. 1 is a longitudinal cross-sectional view of a flocked product of the present invention, and FIG. 2 is an explanatory diagram of a method for measuring the "repulsion elasticity" of a flocked product. 1... Base material, 2... Foamed adhesive layer, 3... Short fibers, 4... Expanded spheres formed by heating and foaming foamable microspheres,
5... Bubbles whipped with air.

Claims (1)

[Claims] 1. A flocked product in which short fibers are flocked on the surface of a base material via a foamed adhesive layer, the foamed adhesive layer comprising:
It contains expanded spheres made by heating and foaming foamable microspheres in which a foamable substance is wrapped in a thermoplastic polymer, and bubbles whipped with air, and the base ends of the flocked short fibers do not reach the base fabric surface. , a flocked product characterized in that it is fixed on the surface of the foam adhesive layer. 2. The hair flocking product according to claim 1, wherein the foamable substance of the foamable microspheres is neopentane. 3. The thermoplastic polymer of the expandable microspheres is a polymer selected from polyvinylidene chloride, a copolymer of vinylidene chloride and acrylonitrile, or a copolymer of acrylonitrile and methyl acrylate. The hair transplant product described in item 1 or 2. 4. Claims 1 to 3, wherein the amount of expandable microspheres is 1 to 3% based on the solid content of the adhesive.
Hair transplantation products described in any of the above.