JPH04316651A - Production of sheet material for forming - Google Patents

Abstract

PURPOSE:To obtain a light-weight sheet material having high-class appearance, excellent handle and formability. CONSTITUTION:A production of forming sheet material characterized by mixing >=30wt.% highly shrinkable polyester based fiber having at least 35% shrinkage factor in warm water kept at >=70 deg.C with 3-35wt.% heat-fusible fiber to prepare a web and subjecting the web to interlacing treatment and then shrinking the highly shrinkable polyester fiber to shrink area of the resultant sheet-like material to >=25% area shrinkage factor of area and then pressurizing the sheet-like material at 70-180 deg.C and temperature higher than the shrinkage temperature so as to enhance apparent density of a nonwoven fabric by >=30% and have at least >=0.20g/cm<2> density and further subjecting the nonwoven fabric to surface treatment.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing sheet materials for forming camera cases, vehicle interior materials, bags, marking materials, clothing materials, and the like.

0002

2. Description of the Related Art Artificial leather, synthetic leather, etc. are used for molded products such as camera cases, vehicle interior materials, and bags. These can be thermoformed or high-frequency molded, and their appearance and
The texture is also luxurious and desirable.

[0003] However, these materials are expensive and heavy because they are made of nonwoven fabrics or woven or knitted fabrics that are impregnated with polyurethane resin, etc., so they cannot meet the demands for weight reduction. It's hard to get something satisfying.

[0004]Furthermore, non-woven fabrics and the like are also used as interior materials for vehicles, but in this case, many of the fabrics are raised and are different from artificial leather.

[0005] Furthermore, when attempting to mold such a nonwoven fabric, since the density of the nonwoven fabric is low, the edge portions during molding may become partially thinned, or the molded product tends to be angular. It is not desirable as there is no problem. Furthermore, a backing material is required to maintain the shape.

[0006]

[Problems to be Solved by the Invention] The present invention is a new material that eliminates the drawbacks of these conventional artificial leathers, synthetic leathers, and nonwoven fabrics, and has a high-quality appearance, excellent texture and moldability, and is lightweight. A sheet-like product is obtained.

[0007]

[Means for Solving the Problems] The present invention consists of ``30% by weight or more of highly shrinkable polyester fibers having a shrinkage rate of at least 35% in hot water of 70°C or higher, and 5% by weight of heat-fusible fibers.
After mixing at a ratio of ~30% by weight to create a web and subjecting it to entanglement treatment, the highly shrinkable polyester fibers are shrunk and the area of the obtained sheet-like material is shrunk to an area shrinkage rate of 25% or more. A sheet material for forming, which is pressurized at 180° C. and higher than the shrinkage temperature to increase its apparent density by 30% or more to at least 0.20 g/cm3 or more, and then surface-processes the sheet material. Production method. ”.

The highly shrinkable polyester fiber used in the present invention is a polyester fiber that shrinks significantly upon heat treatment, and exhibits a shrinkage rate of 35% or more in hot water at 70°C.

[0009] This polyester fiber can be produced by appropriately selecting spinning conditions (cooling conditions, take-up speed), stretching conditions, heat treatment conditions, etc.

The heat-fusible fiber used in the present invention uses two types of thermoplastic synthetic polymers with different melting points, and has a high melting point polymer in the core and a low melting point polymer in the sheath. A core-sheath type composite fiber is preferred, but a single fiber consisting only of a low melting point polymer may also be used. The melting point of the low melting point component which is the adhesive component of this heat-fusible fiber is preferably 180° C. or lower.

[0011] 30% by weight or more of highly shrinkable polyester fibers having a shrinkage rate of at least 35% in hot water of 70° C. or more, and 3 to 35% by weight of heat-fusible fibers, preferably,
It is preferable that the highly shrinkable polyester fibers are mixed in a proportion of 50% by weight or more and the heat-fusible fibers in a proportion of 5 to 25% by weight.

If the amount of highly shrinkable polyester fibers is less than 30% by weight, the shrinkage (area shrinkage rate) of the nonwoven fabric is insufficient and buckles, resulting in molded products with corners or lack of bulk. Become something.

If the amount of heat-fusible fibers is less than 5% by weight, the shape retention properties of the molded article will be poor, and if it exceeds 35% by weight, the molded article will become film-like and lack bulk, which is not preferred.

[0014] When forming the web, two types of fibers, high-shrinkage polyester fibers and heat-fusible fibers, may be used, but low-shrinkage fibers that do not substantially shrink below 130°C are used in combination. As a result, the bulk of the final nonwoven fabric increases, and the relative movement of the fibers increases during shrinkage, pressurization, etc., and the entanglement of fibers caused by needle punching is released, increasing the fiber density. This is preferable because it becomes easier to make the material uniform and wrinkles do not occur during the bending process.

Examples of low-shrinkage fibers that do not substantially shrink below 130°C include polyester fibers and polyamide fibers. It can be manufactured by appropriately selecting conditions, heat treatment conditions, etc.

[0016] It is desirable that both the heat-fusible fiber and the low-shrinkage fiber are polyester fibers.

[0017] The high-shrinkage polyester fiber, heat-fusible fiber, and low-shrinkage fiber may be made of colored polymers.

The web is created by opening the high-shrinkage polyester fiber and heat-fusible fiber, or the high-shrinkage polyester fiber, heat-fusible fiber, and low-shrinkage fiber using an ordinary roller card or the like. However, this can be carried out by mechanically laminating the spun fibers or by laminating them using an air stream or the like.

[0019] In order to perform the entanglement treatment on the web, punching with a barbed needle using a needle rocker or the like is most efficient, but other methods such as using a high-pressure water stream may also be employed.

Next, the entangled web thus obtained is shrunk so that the surface area of the web is reduced by 30% or more.

[0021] If the shrinkage rate of the web surface area is less than 30%, the fiber density will not be uniform enough, the surface uniformity after pressurization will be insufficient, and wrinkles will occur during molding. It is not preferable because it is easy to bend and has inferior bulk.

[0022] It is particularly preferred that the web surface area shrinkage is between 35 and 60%.

[0023] Any method can be used to shrink the web, such as immersing the web in hot water or exposing the web to hot air. There is an excellent way to do this.

After the shrinkage treatment, the web is further pressed at a temperature of 70 to 180° C. while keeping the surface area of the web substantially constant to reduce the apparent density of the nonwoven fabric to 30.
% or more to at least 0.20 g/cm3 or more.

[0025] If the temperature during pressurization is less than 70°C, it is difficult to increase the apparent density of the web to 0.20 g/cm3 or more.

[0026] If the temperature exceeds 180°C, the nonwoven fabric becomes film-like and loses its bulk, which is not preferable.

[0027] As a method of compressing the web, a method of compressing it between flat plates with smooth surfaces such as a flat plate press, cylinder belt press, or roller press, between a cylinder roll and a belt, between cylinder rolls, etc. may be adopted. is necessary.

In this pressing operation, it is necessary to increase the apparent density of the web by at least 30% or more, preferably 50 to 200%, based on the apparent density of the web after the shrinkage treatment. Pressure has the effect of smoothing out unevenness on the web surface caused by entanglement processing such as needle punching, and a uniform appearance can be obtained during finishing.

Furthermore, it has the effect of breaking up the fiber bundles that are caught by the barbs of the needles and pushed into the web in the thickness direction during the entangling process, thereby reducing density unevenness within the web.

If the apparent density of the web is not increased by 30% or more by pressurization, these effects will be small and the uneven fiber density of the web will not be sufficiently reduced, making it impossible to solve the problem of wrinkles occurring during bending.

[0031] Furthermore, uneven coating of colorant during finishing processing,
Problems such as poor adhesion of the film layer and uneven appearance occur.

Furthermore, the apparent density of the nonwoven fabric is at least 0.
It is necessary to increase it to 20 g/cm3 or more.

[0033] If it is not increased to 0.20 g/cm3 or more, it tends to become angular during molding, the molded product lacks roundness, and it is difficult to maintain its shape.

[0034] Preferably 0.30 to 0.70 g/cm
3 is good.

Next, this nonwoven fabric is finished without being impregnated with a polyurethane resin or the like.

[0036] In the finishing process, embossing is performed at a temperature and pressure sufficient to form a pattern on the surface, thereby forming a desired pattern on the surface.

Alternatively, a colored surface is formed by applying a polymer composition containing a coloring agent to a nonwoven fabric by gravure printing or spraying until a desired colored layer is formed.

More preferably, embossing makes the appearance more similar to artificial leather.

Alternatively, a release paper having a desired pattern is coated with a polymer containing a coloring agent, and then an adhesive is coated, this polymer film layer is laminated to a nonwoven fabric, and the release paper is peeled off. It is also possible to perform finishing processing. Furthermore, dyeing processing etc. may be performed,
Other finishing methods can also be used.

The present invention will be further explained below with reference to Examples.

[0041]

[Example 1] An undrawn yarn made by melt-spinning polyethylene terephthalate containing 3% by weight of carbon black at 280°C was stretched 2.5 times in warm water at 55°C, passed through a crimper, coated with an oil agent, and then cut. 2.5 denier 51m
m short fibers were obtained.

This fiber is a highly shrinkable polyester fiber having a shrinkage rate of 52% in hot water at 70°C.

[0043] A polyethylene terephthalate copolymer copolymerized with 35 mol% of isophthalic acid component and having a melting point of 130°C is used as the sheath, and polyethylene terephthalate containing 2% by weight of carbon black is used as the core, 2 denier and fiber length 51 mm. Core-sheath type composite short fibers were used as heat-fusible fibers.

The carbon black-containing unstretched polyester tow used in the production of the above-mentioned highly shrinkable polyester fiber was stretched 4 times in hot water at 93°C, and then stretched 2 times in hot water at 60°C.
．． A tow with a single yarn average fineness of 1.8 denier obtained by stretching 1 times was tensioned and heat set at 180° C., then an oil agent was applied, the tow was crimped, and then cut into 51 mm pieces. The resulting short fibers had a shrinkage rate of 1% under dry heat at 130°C.

[0045] The above three types of fibers were mixed into high shrinkage polyester fiber/thermal fusible fiber/low shrinkage fiber = 70/10/2.
Then, carding and lamination were performed using a card and a cross layerer to obtain a web of 200 g/m2, followed by punching of 800 webs/cm2 in a needle room equipped with a needle.

[0046] Next, this was immersed in hot water at 68°C for 2 minutes, and the web surface area was shrunk by 38% with respect to the original web surface area.

[0047] After that, the water content was reduced to 10 using a suction dehydrator.
0% or less, and then pressure-dried using a cylinder press machine while keeping the web surface area substantially constant, and then dried with hot air to obtain a nonwoven fabric.

[0048] The apparent density of the web is 0.19 g/cm
3, the density of the nonwoven fabric was 0.37 g/cm3, and the increase rate in apparent density was 95%.

Next, this nonwoven fabric was colored by spraying a solution of 5% by weight of black pigmented polyurethane in N,N'-dimethylformamide, and then heated and embossed with a cowhide pattern embossing roll.

[0050] This sheet was cut into squares and molded using a high-frequency welder for camera cases under conditions of 12KW, 1A, and 3 seconds.

The camera case-shaped molded product thus obtained had the same appearance as artificial leather without any sagging and no corners. Furthermore, its basis weight was as light as 560 g/m2.

[0052]

[Comparative Example 1] The high-shrinkage polyester fiber/low-shrinkage fiber used in Example 1 was mixed at a weight ratio of 70/30, and subjected to needle processing, shrinkage processing, and pressurization under the same conditions as Example 1. Drying and hot air drying were performed.

The area shrinkage rate of the obtained sheet was 32% of the original web surface area, and the apparent density was 0.
17g/cm3, and the apparent density of the nonwoven fabric after processing is 0.
It was 32g/cm3. The increase rate in apparent density was about 88%.

[0054] Next, finishing and molding were carried out in the same manner as in Example 1. Although the obtained molded product had an appearance similar to that of artificial leather, it could not maintain its shape as a camera case and had large sag, so it could not be used as a camera case.

[0055]

[Comparative Example 2] The same nonwoven fabric as in Example 1 was impregnated with a 7% by weight N,N'-dimethylformamide solution of polyurethane resin in which 2.5 parts of carbon black was added to 100 parts of polyurethane resin, and a squeeze roll was prepared. After squeezing, the sample was immersed in warm water at 40°C, coagulated, washed, and dried.

When finishing and molding were carried out in the same manner as in Example 1, a camera case with a solid shape and an excellent appearance was obtained, but the basis weight was 900 g/m2, which was heavy.

[0057]

[Example 2] An undrawn yarn obtained by melt-spinning polyethylene terephthalate containing 5% by weight of carbon black at 290°C was stretched 2.3 times in warm water at 63°C, passed through a crimper, and coated with an oil agent. It was then cut to obtain short fibers of 2.0 denier and 51 mm. This fiber was a highly shrinkable polyester fiber with a shrinkage rate of 50% in hot water at 70°C.

[0058] A single yarn fineness of 3 in which a polyethylene terephthalate copolymer copolymerized with 35 mol% of an isophthalic acid component and having a melting point of 130°C is arranged in the sheath part and a polyethylene terephthalate containing 3% by weight of carbon black is arranged in the core part. A core-sheath type composite fiber having a denier and a fiber length of 51 mm was used as the heat-fusible fiber.

[0059] The carbon black-containing unstretched polyester tow used in the production of the above-mentioned highly shrinkable polyester fiber was stretched 3.6 times with a hot pin, further heat-set with a heat plate at 180°C, and then an oil agent was applied and crimped. After that, it was cut into 51 mm pieces (2.5 denier). The shrinkage rate of the obtained short fibers under dry heat at 130° C. was 2%.

[0060] The above three types of fibers were mixed into high shrinkage polyester fiber/thermal fusible fiber/low shrinkage fiber = 65/20/1.
Then, carding and lamination were performed using a card and crosslayer to create a web of 170 g/m2, and 800 webs/m2 were produced in a needle room equipped with a needle.
Punching of cm2 was performed.

[0061] Next, this was immersed in hot water at 70°C for 2 minutes to shrink the web by 40% relative to the original surface area.

[0062] After that, the moisture content was reduced to 10 using a suction dehydrator.
0% or less, and then pressure-dried using a cylinder press machine while keeping the web surface area substantially constant, and then dried with hot air to obtain a nonwoven fabric.

[0063] The apparent density of the web is 0.20 g/cm3
The density of the nonwoven fabric was 0.40 g/cm3, and the rate of increase in apparent density was 100%.

Next, 10% by weight of black pigmented polyurethane
The nonwoven fabric was colored with an N,N'-dimethylformamide solution by a gravure method, and then heated and embossed with a leather-patterned embossing roll.

[0065] This sheet was cut into squares, and heated at 45°C at 200°C using a hot molding plate for marking with the company name.
The marking material was pressed for a second and the shape of the letters was clearly visible. In this marking material, the characters did not disappear even when folded, and the marking material had high form stability.

[0066]

[Comparative Example 3] An attempt was made to finish the same hot air-dried nonwoven fabric as in Example 2 using the same gravure method as in Example 2, but uniform coating could not be achieved due to surface irregularities.

Further, although hot embossing was carried out using an embossing roll, only a product with a poor appearance was obtained because the convex portions were partially fluffed or there were film-like angular portions.

[0068]

[Effects of the Invention] The sheet material obtained by the present invention can be finished in the same way as artificial leather by making a uniform, high-density nonwoven fabric using high shrinkage polyester fibers and heat-fusible fibers. It is a lightweight sheet material with a luxurious appearance, excellent texture and moldability.

Claims (1)

[Claims] Claim 1: A web is prepared by mixing 30% by weight or more of highly shrinkable polyester fibers having a shrinkage rate of at least 35% in hot water of 70°C or higher and 3 to 35% by weight of heat-fusible fibers. After the preparation and entanglement treatment, the highly shrinkable polyester fibers are shrunk to shrink the area of the obtained sheet to an area shrinkage rate of 25% or more, and then at a temperature of 70 to 180°C and higher than the shrinkage temperature. Pressurize to increase its apparent density by 30% or more to at least 0.20 g/cm3
A method for manufacturing a sheet material for molding, which comprises performing the above steps and then subjecting the sheet material to surface treatment.