JP2000328464A - Process release paper sheet for synthetic leather - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a process release paper sheet which is used for imparting a high ebony color and a uniformity to the surface of a synthetic leather and has a sufficient release force required for the production of the synthetic leather. SOLUTION: This process release paper sheet has the coating layer of a binder, for example, comprising a styrene.butadiene copolymer having a gel fraction of >=80% in toluene. A release agent layer formed on a pigment-coated paper sheet having an oil absorbing degree of 200 to 1,000 sec based on JIS P-3,001 contains an inorganic pigment having an average particle diameter of 0.5 to 40 μm as a matting agent, and the surface of the release agent layer has an smoothness of 100 to 500 sec, as determined by the OKEN (ohji Paper Research) method provided for in the J. TAPPI paper pulp test method No.5.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a process release paper for synthetic leather (hereinafter simply referred to as a process release paper) used for forming a surface of the synthetic leather in a synthetic leather manufacturing process.

[0002]

2. Description of the Related Art Synthetic leather is an alternative to industrially produced natural leather. However, synthetic leather can be manufactured in a large quantity with a certain quality compared to natural leather, and there is no restriction on the shape of natural leather. Thus, it is used in a wide range of fields such as clothing, shoes, bags, and sofa.

As one method of producing synthetic leather, a synthetic leather composition, for example, a urethane resin, a vinyl chloride resin, a polyamide resin, an amino acid resin, etc., is applied on a release paper, followed by drying or curing, and then the composition is coated on a paper. A synthetic leather is obtained by applying an adhesive to the varnish, laminating a woven fabric or the like, and then passing between chill rolls and then peeling off the process release paper.

[0004] Synthetic leather manufactured by this manufacturing method can be freely obtained from glossy type to matte type depending on the surface properties of the process release paper. Since the surface shape of the synthetic leather is formed by transferring the surface of the process release paper to be used, the quality of the surface of the process release paper is important. Among these process release papers, jet-blackness can be cited as a quality particularly required for the matte type, but when producing a synthetic leather of a dark color, for example, black, the quality of the surface of the process release paper is selected. It expresses the shade of the color tone of synthetic leather obtained by its smoothness and surface smoothness. It is said that the darker the tone, the higher the jet-blackness, the better the texture, and the higher the quality.

[0005] A release paper used for forming the surface of a matte type synthetic leather is coated with a release agent obtained by adding an inorganic pigment such as silica or calcium carbonate as a matting agent to a support to form a release agent layer. Obscene types are well known.

As the support, a simple substance such as paper, a polymer film, a metal foil, or a combination thereof is used. However, paper which is advantageous in performance and cost is widely used. It is a target. And, conventionally, when using a support such as paper, which easily penetrates the release agent,
It is common to apply an organic binder component or a mixture of an organic binder component and a pigment before providing a release agent layer and perform a sealing treatment, so that the release agent does not penetrate into the support, and a good release is achieved. This filling process is performed for the purpose of maintaining the property.

However, the surface of the process release paper obtained by such a method has high gloss and high smoothness.
The color tone of the resulting synthetic leather is light, and the problem of low jet blackness tends to occur. In addition, in order to obtain sufficient jet-blackness, a method of increasing the content of the delustering agent in the release agent component can be considered, but a peeling failure due to a decrease in the peelability of the process release paper, specifically, Dirt on the surface of the process release paper due to inking,
Problems such as the substrate being easily broken and the coated surface becoming non-uniform occur. For this reason, there is a strong demand for a process release paper that imparts high jetness and uniformity to the synthetic leather surface and has a necessary and sufficient release force. However, a process release paper satisfying these requirements has not been found at present.

[0008]

SUMMARY OF THE INVENTION An object of the present invention is to provide a process release paper which imparts high jetness and uniformity to a synthetic leather surface and has a necessary and sufficient release force.

[0009]

SUMMARY OF THE INVENTION In view of such circumstances, the present inventors have provided seemingly contradictory properties of imparting high jet-blackness and uniformity to a synthetic leather surface and having a necessary and sufficient peeling force. In order to obtain a process release paper, as a result of extensive research on the support, properties of the release agent, application method and application conditions, etc., it imparts high jet blackness and uniformity to the synthetic leather surface, and has a necessary and sufficient release force. The present invention has completed a method for producing an excellent synthetic leather process release paper having good release properties and has led to the present invention.

That is, according to the present invention, the support for the process release paper is
Oil absorption based on JIS P-3001, 200 to 10
The pigment-coated paper is in the range of 00 seconds, and the styrene-butadiene copolymer latex used as a binder in the coating layer of the pigment-coated paper has a gel weight fraction to toluene of 80% or more, and The release agent layer formed on the surface of the process release paper contains an inorganic pigment having an average particle size of 0.5 to 40 μm as an anti-glazing agent. TAPP
I pulp test method No. The process release paper characterized in that the Oken type smoothness specified in No. 5 is in the range of 100 to 500 seconds.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention relates to a process release paper which is classified into a mat type among process release papers and has an unprecedented uniform and high quality matte surface.

In order to obtain a process release paper having a high jet-blackness and uniformity on the surface of synthetic leather, which is the object of the present invention, and to have a necessary and sufficient release force, the inventors of the present invention have to apply a release agent before applying a release agent. The physical properties of the support, the composition of the release agent, and the process after applying the release agent.As a result of a detailed examination of the relationship between the physical properties of the release paper and the jet-blackness of the synthetic leather obtained, the jet-blackness of the synthetic leather was The oil absorption and the average particle size of the matting agent in the release agent, the smoothness of the resulting release paper surface are closely related, and the release force is
It has been found that the oil absorption of the support is closely related to the gel weight fraction of the styrene / butadiene copolymer latex as a binder used in the support coating layer with respect to toluene.

Further, the inventors of the present invention have determined the relationship between jet-blackness of synthetic leather, oil absorption of the support, average particle size of the matting agent in the release agent, smoothness of the obtained process release paper surface, and release. As a result of intensive studies on the relationship between the force, the oil absorption of the support, and the gel weight fraction of styrene / butadiene copolymer latex used as a binder in the support coating layer with respect to toluene, all these relationships were found to be the present invention. For the first time, it has been found that by providing a synthetic leather surface with high jetness and uniformity, and to obtain a process release paper having a necessary and sufficient release force, the present invention has been completed. .

The support of the process release paper in the present invention is a paper machine called a fourdrinier multi-cylinder paper machine, a cylindrical multi-cylinder paper machine, a fourdrinier yankee type paper machine, or a round rope yankee type paper machine. On a base paper mainly composed of wood pulp, having a pigment coating layer coated with a coating layer component on a coating machine connected to or separated from the rear of these paper machines. ,
Among those classified as pigment-coated paper for printing by the Japan Pulp and Paper Federation, it is necessary that the oil absorption based on JISP-3001 be in the range of 200 to 1000 seconds.

These pigment-coated papers are obtained by coating the above-mentioned base paper with pigments such as kaolin, calcium carbonate, talc, silica, barite powder, alumina white, tisane white, aluminum hydroxide, titanium oxide, and styrene-butadiene. It is produced by providing a pigment coating layer prepared by appropriately combining a binder mainly composed of a copolymer latex.

The styrene / butadiene copolymer latex used as a binder in the coating layer of the pigment coated paper must have a gel weight fraction to toluene of 80% or more. When the filler layer of the support does not contain a pigment and is coated only with a binder, the smoothness of the process release paper of the present invention cannot be easily obtained, and the surface after the release agent is coated is not obtained. The surface becomes extremely rough, and it is impossible to obtain a uniform synthetic leather surface excellent in jet-blackness.

[0017] Even if a glossiness treatment facility called a machine calender or a super calender obtains a smoothness within the range of the present invention, the surface swelling may occur due to the swelling of the surface during the application of the synthetic leather manufacturing resin in the synthetic leather manufacturing process. It restores to a rough surface and cannot impart jet-blackness and uniformity to the synthetic leather surface.

When the oil absorption of the support is 200 seconds, the penetration of the release agent when the release agent is coated on the support increases, and a sufficient release agent layer is not formed on the support. When peeling synthetic leather obtained by using such a process release paper, a sufficient release force cannot be obtained, resulting in a very heavy release. On the other hand, when the oil absorption of the support is more than 1000 seconds, the matting agent in the release agent is not exposed to the release agent layer surface because the penetration of the release agent is small. The smoothness is increased, and the jet-blackness of the resulting synthetic leather is reduced. Further, as the drying time of the release agent becomes longer, the matting agent in the release agent is liable to agglomerate, and the coated surface tends to be uneven.

When the gel weight fraction with respect to toluene of the styrene / butadiene copolymer latex used as a binder in the pigment coating layer of the support is less than 80%, the oil absorption of the support falls within a specific range. Even if there is, the penetration of the release agent when applying the release agent on the support increases,
A sufficient release agent layer is not formed on the support, and a sufficient release force cannot be obtained when the synthetic leather obtained by using such a release paper is released, resulting in a very heavy release.

Here, the gel weight fraction based on toluene is a value obtained by the following method. The styrene-butadiene copolymer latex used as a binder is formed on a Teflon sheet so that the film thickness is 0.3 to 0.5 mm (after drying). Drying conditions are 50 ° C./24 hours. Next, the film formed under the above conditions was
Cut into squares, immersed in toluene for 24 hours,
Dry for more than an hour to completely volatilize the solvent and measure the weight change before and after immersion. The following formula

The gel weight fraction is determined by the following equation.

[0021]

(Equation 1)

The release agent applied to the support of the step release paper in the present invention may contain an inorganic pigment having an average particle size in the range of 0.5 to 40 μm as a matting agent in the release agent. Desired. Inorganic pigments used as antiques agents include, for example, kaolin, talc, silica, gypsum,
Barite powder, alumina white, titanium oxide, calcium carbonate and the like can be mentioned, and among these inorganic pigments, those having an average particle diameter in the range of 0.5 to 40 μm can be appropriately selected and used. The average particle size of the inorganic pigment is 0.5 μ
m, the J.M. of the surface of the obtained process release paper. TAPP
I pulp test method No. When the Oken-type smoothness specified in 5 becomes greater than 500 seconds and synthetic leather is produced,
Sufficient jet-blackness cannot be obtained. Further, when it is larger than 40 μm, the above-mentioned Oken type smoothness of the obtained process release paper is 100
Seconds, the unevenness of the process release paper surface increases, so that the jet-blackness of the synthetic leather increases, but the strength of the release agent layer applied on the support decreases, the matting agent drops off, and the synthetic leather surface Transfer occurs.

The release agent component is not particularly restricted but includes, for example, silicone, alkyd resin, alkyd / silicone copolymer, silicone-modified amino alkyd resin as disclosed in JP-A-2-28242, and silicone. A modified aminoacrylic resin, a mixture thereof and the like can be used.

Further, the content of the matting agent in the release agent is not limited since it is selected according to the quality demand of the synthetic leather to be obtained.

Further, the curing of the release agent of the present invention is generally carried out by a heat curing method using an acid catalyst such as paratoluenesulfonic acid, hydrochloric acid or the like, but it can also be cured by using an ultraviolet ray or an electron beam.

In addition, various auxiliaries such as a dye, an ultraviolet absorber, an antifoaming agent, a leveling agent, and an antistatic agent can be added as long as the effects of the present invention are not impaired.

When applying this release agent on a support,
In general, it is convenient to apply as a solvent solution in use, and the solvent used for this purpose may be any solvent that does not react with the release agent component, such as benzene, toluene, xylene, methanol, ethanol, and isobutanol. , Normal butanol, methyl ethyl ketone, acetone, tetrahydrofuran or the like, or a mixture of two or more thereof, is used in an amount of usually 10% of the solid content of the release agent depending on the method of applying the release agent on the support. It is adjusted to be in the range of ６０60%.

The coating method is not particularly limited, but includes a dutter coat, a blade coat, an air knife coat, a squeeze coat, a reverse roll coat, a gravure roll and a transfer roll coat, a four or five roll coat, a curtain coat, and an extrusion. Any method such as a coat, a die coat, a lip coat, a U comma coat, and a micro gravure coat may be used.

The amount of the release agent in the release agent layer formed on the support varies depending on the type of the support.
It is formed in the range of 0 g / m ² . When the amount of the release agent is less than 1 g / m ² , it is difficult to uniformly form the release agent layer on the support, and the release property is deteriorated. Also,
Even if the amount exceeds 20 g / m ² , the characteristics do not change and the cost increases, which is not preferable.

[0030]

EXAMPLES The present invention will be described in more detail with reference to the following Examples, which should not be construed as limiting the scope of the present invention. In the examples, “parts” means “parts by weight”.
Is shown.

Example 1 A pigment having an oil absorption of 220 seconds as a support, a gel weight fraction of a styrene / butadiene copolymer used as a binder in a pigment coating layer of 84%, and a basis weight of 157 g / m ² was used. Using coated paper (manufactured by Oji Paper Co., Ltd., trade name: OK Top Coat Dal), 100 parts of an aminosilicone-modified alkyd resin (manufactured by Shin-Etsu Chemical Co., Ltd., trade name: KS-883) is coated with granular silica (average particle size: 3 μm) 25 Parts, 4 parts of p-toluenesulfonic acid as an acid catalyst, 6 g / m ^{2 of} a release agent coating solution adjusted to a solid concentration of 30% using toluene as a solvent was applied to the support, and heated to 170 ° C. And dried for 30 seconds to produce a process release paper. On this release paper, 7 parts of a crosslinking agent (manufactured by Nippon Polyurethane Industry, trade name: Coronate L) was added to 100 parts of a polyurethane resin (manufactured by Nippon Polyurethane Industry, trade name: Nipporan 5034), and 5 parts of pigment were further added. Thereafter, 30 parts of ethyl acetate was added to dilute the mixture, the solid content was applied using a knife coat at 50 g / m ^{2, the} base fabric was laminated, dried and aged for 48 hours, and the release paper was peeled off to produce synthetic leather. Table 1 shows the results.

Example 2 As a support, a pigment-coated paper having an oil absorption of 950 seconds, a gel weight fraction of a binder in the pigment coating layer of 87%, and a basis weight of 157 g / m ² (trade name, manufactured by Oji Paper Co., Ltd.) : OK Dune Art) to apply a release agent coating solution of Example 1 at 6 g / m ² to prepare a process release paper. On this release paper, a one-component polyurethane solution (manufactured by Dainippon Ink and Chemicals, Inc., product name: Chrisbon 7667EL) is applied by knife coating so that the applied film thickness becomes 30 μm, and the base fabric is laminated and dried, and dried for 48 hours. After aging, the process release paper was peeled off to produce synthetic leather. Table 1 shows the results.

Example 3 As a support, a pigment-coated paper having an oil absorption of 550 seconds, a gel weight fraction of a binder in the pigment coating layer of 82%, and a basis weight of 165 g / m ² (trade name, manufactured by Oji Paper Co., Ltd.) : OK Golden Matt), 100 parts of aminosilicone-modified alkyd resin (trade name: KS-883, manufactured by Shin-Etsu Chemical Co., Ltd.), 30 parts of granular silica (average particle size: 0.6 μm), and paratoluenesulfonic acid 4 as an acid catalyst Parts, and a release agent coating liquid adjusted to a solid content concentration of 80% using toluene as a solvent was applied in an amount of 6 g /
It created a process release paper and m ² coated. This process release paper,
Table 1 shows the results of synthetic leathers produced using the same.

Example 4 A pigment-coated paper having an oil absorption of 550 seconds, a gel weight fraction of the binder in the pigment coating layer of 82%, and a basis weight of 165 g / m ² (trade name, manufactured by Oji Paper Co., Ltd.) was used as a support. : OK Golden Matt), 100 parts of aminosilicone-modified alkyd resin (trade name: KS-883, manufactured by Shin-Etsu Chemical Co., Ltd.), 18 parts of granular silica (average particle size: 38 μm), and 4 parts of paratoluenesulfonic acid as an acid catalyst Then, 6 g / m ^{2 of} a release agent coating liquid adjusted to a solid concentration of 30% using toluene as a solvent.
Coating was performed to produce a process release paper. Table 1 shows the results of this process release paper and the synthetic leather produced using the same.

Example 5 100 parts of a silicone-modified alkyd resin (trade name: X-62-950, manufactured by Shin-Etsu Chemical Co., Ltd.) was used as a releasing agent in 30 parts of granular silica (average particle size: 2 μm), and paratoluenesulfonic acid 4 was used as an acid catalyst. The process release paper was prepared in the same manner as in Example 1 except that a release agent coating solution was used, which was prepared by adjusting the solid content concentration to 30% using toluene as a solvent. Table 1 shows the results of this process release paper and the synthetic leather produced using the same.

Comparative Example 1 Dalmat coated paper (Oji Paper Co., Ltd .; trade name: oil absorption 180 seconds, gel weight fraction of binder in pigment coating layer 79%, basis weight 156 g / m ² ) : Satin Kanto)
Was used to apply the release agent coating solution of Example 1 at 8 g / m ² to prepare a process release paper. Table 1 shows the results of this process release paper and the synthetic leather produced using the same.

Comparative Example 2 As a support, an enamel-coated paper having an oil absorption of 1050 seconds, a gel weight fraction of a binder in the pigment coating layer of 88%, and a basis weight of 120 g / m ² (trade name, manufactured by Oji Paper Co., Ltd.) : OK mirror coat platinum), 6 g of the release agent coating liquid of Example 1
/ M ^{2 was} applied to prepare a process release paper. Table 1 shows the results of this process release paper and the synthetic leather produced using the same.

Comparative Example 3 A pigment-coated paper having an oil absorption of 550 seconds, a gel weight fraction of the binder in the pigment coating layer of 82%, and a basis weight of 165 g / m ² (trade name, manufactured by Oji Paper Co., Ltd.) was used as a support. : OK Golden Matt), 100 parts of aminosilicone-modified alkyd resin (trade name: KS-883, manufactured by Shin-Etsu Chemical Co., Ltd.), 30 parts of granular silica (average particle size: 0.4 μm), and paratoluenesulfonic acid 4 as an acid catalyst Parts of a release agent coating liquid adjusted to a solid content concentration of 30% using toluene as a solvent, at 6 g / m
^Two coatings were made to produce a process release paper. Table 1 shows the results of this process release paper and the synthetic leather produced using the same.

Comparative Example 4 As a support, a pigment-coated paper having an oil absorption of 550 seconds, a gel weight fraction of a binder in the pigment coating layer of 82%, and a basis weight of 165 g / m ² (trade name, manufactured by Oji Paper Co., Ltd.) : OK Golden Mat), 100 parts of aminosilicone-modified alkyd resin (trade name: KS-883, manufactured by Shin-Etsu Chemical Co., Ltd.), 18 parts of granular silica (average particle size: 45 μm), and 4 parts of paratoluenesulfonic acid as an acid catalyst Then, 6 g / m ^{2 of} a release agent coating liquid adjusted to a solid concentration of 30% using toluene as a solvent.
Coating was performed to produce a process release paper. Table 1 shows the results of this process release paper and the synthetic leather produced using the same.

Comparative Example 5 Except for using a paper having a pigment-free coating layer having an oil absorbency of 550 seconds, a binder of the coating layer having a gel overlay ratio of 82%, and a basis weight of 165 g / m ² as a support, In the same manner as in Example 1, 6 g / m ² of a release agent coating solution was applied to prepare a process release paper. Although the surface smoothness of this release paper was 150 seconds, the smoothness was adjusted to 250 seconds using a spar calendar. Table 1 shows the results of this process release paper and the synthetic leather produced using the same.

[0042]

[0043]

As can be seen from Table 1, according to the present invention, it is possible to obtain a process release paper which imparts high jetness and uniformity to the surface of synthetic leather, and has a necessary and sufficient release force when producing synthetic leather.

Claims (1)

[Claims] 1. A process release paper for synthetic leather, wherein the support of the process release paper is a pigment-coated paper having an oil absorption based on JIS P-3001 in the range of 200 to 1000 seconds. The styrene-butadiene copolymer latex used as a binder in the coating layer of the paper has a gel weight fraction of 80% or more with respect to toluene, and the release agent layer formed on the support has an average particle size as a matting agent. 0.5 ~
It contains an inorganic pigment in the range of 40 μm and has a J.I. TAPPI paper pulp test method No. 5. A process release paper for synthetic leather, wherein the Oken type smoothness specified in 5 is in the range of 100 to 500 seconds.