JPH0327677B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method for producing a process release paper that can be repeatedly used in the production of PVC foam leather sheets. Since polyvinyl chloride foam leather is cheaper than natural leather, it has been used as a furniture decoration material since the late 1950s.
It is widely used for automobile interior materials, clothing, patch tensions, tapes, etc. The structure of this foamed leather includes foamed PVC sheet, skin/foamed PVC, skin/cloth/foamed PVC,
Foamed PVC/cloth, skin/foamed PVC/felt, etc.
They vary depending on the application, such as those with a single layer of foamed PVC and those with a multilayer structure. Foaming compound and foaming PVC plastisol are used as raw materials for manufacturing this foamed PVC. In addition, the manufacturing method for foamed PVC leather is described in detail on pages 327 to 376 of Plastics's "Material Course" 18 "Vinyl Chloride Resin" by Masatoshi Furuya (February 20, 1976, published by Nikkan Kogyo Shimbun). ing. As a method for manufacturing leather using such expanded PVC plastisol, a process release paper with a silicone resin or aminoalkyd resin layer provided on the surface of long-fiber wood-free paper is used as a carrier, and a reverse roll coater is used to coat the surface of the process release paper to a certain level. A thick PVC plastisol film is cast, the sol film is gelled in a melting furnace and then cooled, the PVC leather sheet thus formed is peeled off from the process release paper and wound onto a roll, while the process A manufacturing method is used in which the release paper is also wound onto a separate roll and reused. During this production, if necessary, the fabric is laminated to an ungelled sol sheet before entering the melting furnace, or to a gelled sheet immediately after exiting the furnace [Modern
Plastics, 41(3), 84 (Nov.1963)]. In the process release paper used in this PVC leather manufacturing method, silicone resin (linear polymer of siloxane diol) is used as the resin that forms the release layer.
Although the silicone resin has excellent heat resistance, it has the disadvantage that when used repeatedly, the silicone resin gradually falls off from the peeling process and the peelability from the leather sheet decreases. Furthermore, the surface gloss of the leather sheet obtained is inferior to that using aminoalkyd resin, making it unsuitable for producing enamel-type leather. Processed release paper using amino alkyd resin provides leather with excellent gloss, but improvements in release properties and heat resistance are desired. In addition, aminoalkyd resin requires a coating amount of 25 to 30 g/m ² while silicone resin has a coating amount of 1 g/m ² .
High cost. The present inventor speculates that if a photocurable resin is used as the resin that imparts releasability, the amount of coating can be reduced and a coating film with excellent heat resistance can be provided. Paper is impregnated with a varnish prepared using epoxy acrylate resin mixed with a solvent and a photosensitizer, dried,
Subsequently, it was found that the process release paper obtained by photo-curing after embossing was affected by solvents such as methyl ethyl ketone and dimethyl formamide contained in PVC plastisol for manufacturing leather sheets. The inventor then investigated various photocurable resins and found that process release paper manufactured using a melamine group-containing acrylamide compound has excellent release properties from leather, and has been found to be suitable for use with enamel (strong gloss) type leather. The present invention has been achieved based on the discovery that the present invention is capable of providing the same properties and has excellent chemical resistance. That is, the present invention provides a varnish (A) component having the following composition. [In the formula, R is a methyl group, a phenyl group,

[Formula] or an organic group represented by the following formula. Y each represents hydrogen or Z ¹¹ . ^Z1 to ^Z11 each represent _-CH2NHCOCR1 = _CH2 , _-CH2OH ^or _-CH2OR2 ^. At least two of ^Z1 to ^Z11 are _-CH2NHCOCR1 ⁼ _CH2 .
R ¹ represents -H or -CH ₃ , R ² has 1 carbon number
~4 alkyl group] Melamine group-containing acrylamide compound represented by 30-90% by weight (B) Component Organic solvent that dissolves the above (A) component 70-10% by weight (C) Component Photosensitizer ( After applying 0.05 to 5% by weight of component A) on paper, drying to remove the organic solvent of component (B) from the paper, then embossing the paper and irradiating the paper with light to remove component (A). The present invention provides a process for producing a release paper, which comprises photopolymerizing a melamine group-containing acrylamide compound. In the practice of the present invention, the melamine group-containing acrylamide compound of component (A) represented by the general formula [] of the varnish component is a methylolmelamine compound or an alkyl etherified melamine compound represented by the following formula [], acrylamide and α - an acrylamide-based compound selected from the group consisting of lower alkyl-substituted acrylamides at a ratio of 2 to 6 moles of the latter to 1 mole of the former, at 50 to 150°C;
Preferably, it is a vinyl monomer that is solid at room temperature (20°C) and is obtained by reacting at a temperature of 100 to 130°C in the presence of a catalyst (Japanese Patent Application Laid-Open No. 55-113664
(see issue). In the formula, each R' is H or has 1 to 4 carbon atoms.
represents a hydrocarbon group, R is a methyl group, a phenyl group, -N(CH ₂ OR') ₂ (R' is the same or different H or a hydrocarbon group having 1 to 4 carbon atoms as R' above), or Indicates an organic group represented by the following formula. (Y is -CH ₂ OR' or hydrogen, R' is H that is the same or different from R' above, or has 1 to 1 carbon atoms, respectively.
4 hydrocarbon group). The reaction time varies depending on the distillation rate of the alkanol (R'OH) generated as the reaction progresses, but is about 2 to 20 hours when the alkanol is methanol. This reaction can be carried out without using a solvent, but it can also be carried out using an organic solvent as the component (B) of the varnish as a solvent. The methylolmelamine compound or the alkyl etherified melamine compound represented by the above general formula [] has already been industrially produced in large quantities, and is widely used mainly in the paint field as a crosslinking agent for various alkyds, acrylic polymers, etc. It is easy to obtain from wherever you are. Some specific examples of the methylolated melamine compound and the alkyl etherified melamine compound are as follows. Hexamethylolmelamine, pentamethylolmelamine, tetramethylolmelamine, trimethylolmelamine, dimethylolmelamine, hexamethoxymethylmelamine, pentamethoxymethylmelamine, tetramethoxymethylmelamine, rimethoxymethylmelamine, tributoxymethylmelamine, hexaethoxymethylmelamine, Pentaethoxymethylmelamine, tetraethoxymethylmelamine, trimethoxymethyl-diethoxymelamine, triethoxymethyl-dibutoxymethylmelamine, hexapropoxymethylmelamine, tripropoxymethylmelamine, dibutoxymethylmelamine, trimethoxymethylmelamine, dipropoxymelamine , hexabutoxymethylmelamine, monomethoxymethylmelamine, tetrabutoxymethylmelamine, tetramethoxymethylmelamine, methylguanamine, dimethoxymethylguanamine, dibutoxymethylguanamine, monomethoxymethylguanamine, tripropoxymethylguanamine, tetramethoxymethylguanamine, benzoguanamine, Tetrabutoxymethylguanamine, dibutoxymethyl-benzoguanamine and mixtures thereof. Particularly suitable for the purposes of the present invention are those of the formula [] in which R' is a methyl group and R is -N(CH ₂ OCH ₃ ) ₂ or a phenyl group. Next, examples of acrylamide and α-lower alkyl-substituted acrylamide include acrylamide, methacrylamide, α-propylacrylamide,
α-Butylacrylamide, and mixtures thereof are generally suitable. As the α-lower alkyl group, those having 1 to 4 carbon atoms are generally suitable. Mixtures of these can also be used. The molar ratio of the acrylamide compound to the methylolated melamine compound or the alkyl etherified melamine compound is about 2 to 6, preferably 3 to 6. At around 1.5, only a viscous product can be obtained at room temperature. By setting it as 2 or more, a melamine group-containing acrylamide compound having a melting point of 50 to 115°C can be obtained. If the photocurable resin is liquid or viscous at room temperature, the resin will adhere to the embossing roll or the embossing press plate when embossing the paper after impregnating with varnish and removing the solvent. As a catalyst, those effective for forming an ester from a carboxylic acid and an alkanol are generally suitable, but a particularly preferred one is one consisting of an organic acid represented by para-toluenesulfonic acid. For example, in the case of para-toluenesulfonic acid, the amount of catalyst used is usually about 100 ppm to 1% by weight, preferably about 1000 to 5000 ppm, based on the total amount of the compound [] and the acrylamide compound. Next, as the organic solvent of component (B) for dissolving the melamine group-containing acrylamide compound, benzene,
Examples include aromatic hydrocarbons such as toluene and xylene, methyl isobutyl ketone, cyclohexanone, dioxane, and tetrahydrofuran. These organic solvents have a boiling point of 90~90 to facilitate volatilization during drying.
A temperature of 150°C is preferred. Next, as the photosensitizer for component (C), there are various photosensitizers that are already used as sensitizers for ultraviolet curable paints, such as benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, α-methylbenzoin,
Benzoin compounds such as α-phenylbenzoin; anthraquinone compounds such as anthraquinone and methylanthraquinone; benzyl; diacetyl; phenyl ketone compounds such as acetophenone and benzophenone; sulfide compounds such as diphenyl disulfide and tetramethylthiuram sulfide; Examples include α-chloromethylnaphthalene; anthracene and halogenated hydrocarbons such as hexachlorobutadiene and pentachlorobutadiene. Among these, benzoin compounds such as benzoin ethyl ether and benzophenone compounds are preferred from the viewpoint of cost and curability. The composition ratio of the components of the varnish is 30 to 90% by weight, preferably 40 to 70% by weight of the photocurable resin (A), and (B)
The organic solvent content of the ingredients is 70-10% by weight, preferably 60-10% by weight.
The amount of the photosensitizer (C) is 0.05 to 5% by weight of the photocurable resin (A). If necessary, an accelerator may be added in an amount of 0.01 to 5% by weight. Generally, the components are prepared so that the varnish has a viscosity of 30 to 5000 centipoise at 25°C. That is, if the amount of organic solvent in component (B) is extremely small relative to the resin content in component (A), the viscosity of the varnish will become high, making it difficult to coat or impregnate paper. On the other hand, if there is too much, drying takes a long time and is not economical. In addition to these components (A) to (C), the varnish contains phenols such as hydroquinone, t-butylhydroquinone, catechol, and hydroquinone monomethyl ether; quinones such as benzoquinone and diphenylbenzoquinone; phenothiazines; and polymerization inhibitors such as copper. Incorporation of such agents improves storage stability. Furthermore, various auxiliary agents such as a viscosity modifier, a surfactant, and an antifoaming agent may be added as necessary. It is also possible to blend polymers such as silicone resin, wax, and styrene-butadiene rubber. Next, manufacturing process release paper using varnish involves coating and impregnating the surface of the paper with varnish at 3 to 10 g/ ^m2 using a roll, spray gun, brush, etc., and then adjusting the temperature at which the organic solvent evaporates. For example 100~150℃
The impregnated paper is introduced into a drying oven set at This is achieved by photopolymerizing the melamine group-containing acrylamide compound contained in the impregnated paper. Papers to be coated and impregnated with varnish include chemical pulp paper, high-quality paper, coated paper, lightweight coated paper,
Examples include art paper, Kent paper, printing paper, etc.
Among these, coated paper that can be easily impregnated with varnish;
Coated paper such as lightweight coated paper or art paper is better. Coated paper is a base paper (including synthetic paper) whose surface is coated with a mineral white coating such as barium sulfate, clay, satin white, calcium carbonate, etc., and a binder such as casein, gelatin, starch, SBR latex, etc.
Coat with acrylic ester/styrene copolymer emulsion, polyvinyl acetate emulsion, vinyl acetate/acrylic ester copolymer emulsion, etc. to a coating amount of 3 to 40 g/ ^m2 , and dry to improve printability. It has a coating film that has been given with a coating film, and is easily available on the market. Embossing is carried out in a conventional manner using a pair of embossing rolls consisting of a metal roll and a paper roll, for example, at a temperature of 20 to 150°C and a pressure of 10 to 50 kg/cm ² . Embossing on one side is sufficient, but embossing on both sides may be sufficient. The embossed pattern creates the desired pattern on the artificial leather. In the practice of the present invention, the paper contains
Since the photocurable resin of component (A) is solid at room temperature,
By setting the temperature of the embossing roll below the softening point of the photocurable resin, adhesion of the resin to the embossing roll is prevented. The light used to cure the photocurable resin of component (A) contained in the embossed paper includes high-energy ionizing radiation and ultraviolet rays having an energy of at least 100 KeV. Examples of high-energy ionizing radiation sources include:
Kotskucroft type accelerator, Vandegraaf type accelerator, linear accelerator, betatron,
Electron beams accelerated by accelerators such as cyclotrons are the most convenient and economical to use industrially, but other sources include radioactive isotopes and γ-rays, X-rays, α-rays, β-rays emitted from nuclear reactors, etc. ray, neutron beam,
Radiation such as proton beams can also be used. Examples of ultraviolet sources include ultraviolet fluorescent lamps, low-pressure mercury lamps, high-pressure mercury lamps, ultra-high-pressure mercury lamps, xenon lamps, carbon arc lamps, and sunlight. The process release paper manufactured in this way has excellent chemical resistance, heat resistance, and releasability from PVC leather. It can also provide enamel leather, which is useful as a process release paper for the production of PVC leather. Hereinafter, the present invention will be explained in more detail with reference to Examples. Note that all parts in the examples are based on weight. Example of manufacturing photocurable resin (component A + component B) Example 1 A four-necked flask is equipped with a stirrer, a thermometer, a cooler, and a glass tube for blowing air. Chemical Cymel 303 266.4 parts (0.68 mol), acrylamide 233.6 parts (3.29 mol), cyclohexanone 500
1 part, 2 parts of para-toluenesulfonic acid, and 0.5 part of hydroquinone were charged, and the temperature was gradually raised to 100°C while blowing air at a rate of 200 ml/min, and the reaction was completed by maintaining the same temperature for 7 hours. After the reaction was completed, the mixture was cooled to 70°C, 20g of sodium bicarbonate was added, and this temperature was maintained for 30 minutes. Thereafter, it was filtered through paper to obtain a resin solution. The viscosity of this resin solution is
160 cps (25°C), and the melting point of the resin from which the solvent was evaporated was 115°C. Examples 2 to 6 Resin solutions were obtained in the same manner as in Example 1, except that the blending ratios of hexamethoxymethylmelamine, acrylamide, and the solvent were changed as shown in Table 1. Examples 7 to 12 Same procedure as in Example 1 except that the amounts of hexamethoxymelamine and acrylamide used were 1 mol and 4.0 mol, respectively, and the amount of cyclohexanone in the varnish was changed to 9.1 to 75% by weight. A resin solution having a viscosity shown in Table 1 was obtained. Example 13 Same as Example 1 except that hexamethylolmelamine was used in place of hexamethoxymethylmelamine at 259 parts (0.85 mol) and acrylamide was used in an amount of 241 parts (3.39 mol).
A resin solution of 150 cps was obtained. The melting point of the resin from which the solvent was removed was 110°C. Example 14 Bisphenol A diglycidyl ether “Epicote 1004” manufactured by Yuka Ciel Epoxy Co., Ltd. (trade name,
464 parts of epoxy equivalent (913), 37 parts of acrylic acid, 1 part of hydroquinone monomethyl ether, 5 parts of tetramethylbenzylammonium bromide, and 500 parts of methyl isobutyl ketone were placed in a 4-necked flask (1), stirred, reflux condenser, and air blown. Attach a tube and thermometer and heat while stirring and blowing air at a rate of 200 ml/min.
The temperature was raised to 110℃. After reacting at the same temperature for 5 hours, the viscosity (25℃) was 280cps.
An epoxy acrylate resin solution was obtained. In addition,
The melting point of the resin from which the solvent was removed was 75°C.

[Table] Examples 1 to 10, Comparative Examples 1 to 4 Photosensitizer 2,2-dimethoxy-2-phenylacetophenone "Irgakyure 651" was added to 100 parts of the resin solution obtained in Production Examples 1 to 14 above. A varnish was prepared by blending 1.5 parts of "(trade name, manufactured by Ciba Geigy). These varnishes were applied to the surface of coated paper with a basis weight of 130 g/m ² using a Meyer bar, dried at 150°C (120°C in the case of epoxy acrylate) to volatilize the solvent, and then embossed. A process release paper was obtained by irradiating ultraviolet rays generated from a mercury lamp and photocuring (the amount of resin applied was 5 g/solid).
^m2 ). These processed release papers were evaluated by the following method. The results are shown in Table 2. Chemical resistance: When the surface of the process release paper is rubbed back and forth 100 times with gauze impregnated with methyl ethyl ketone,
Those with no abnormalities on the surface were evaluated as good, and those with abnormalities on the surface where the surface of the coated paper was exposed were evaluated as poor. Gloss, peelability, heat resistance: After coating the surface of the process release paper with foamed PVC plastisol manufactured by Sumitomo Chemical Co., Ltd. to a thickness of 200μ using a reverse roll, it was heated at 200℃, and then heated at 30℃.
After cooling to 0.degree. C. to form a leather sheet, the leather sheet was peeled off from the process release paper at a speed of 200 mm/min. The gloss of the leather sheet obtained from the process release paper that was used repeatedly 5 times (95° or more good, less than 95° bad) and the ease of peeling the leather (150g/3
(Those with a width of less than cm were considered good; those with a width exceeding 150 g/3 cm were judged as poor) and the presence or absence of thermal deformation of the release paper (those without were judged as good). Comparative Example 5 Coating agent for process release paper as varnish “TESBIL”
SP2504” [glossy amino acrylic resin, product name manufactured by Isojima Essential Oil Co., Ltd.] 100 parts and dryer #50 for 5
30g of this on coated paper.
m ² and heat-cured at 130°C to obtain process release paper. This process release paper was evaluated in the same manner as in Example 1. The results are shown in Table 2.

[Table] * Due to repeated use, the surface of the process release paper is damaged by the solvent in the PVC plastisol, resulting in
The gloss of the leather was reduced.

Claims (1)

[Claims] 1 Varnish (A) component having the following composition General formula: [In the formula, R is a methyl group, a phenyl group,
[Formula] or an organic group represented by the following formula. Y each represents hydrogen or Z ¹¹ . ^Z1 to ^Z11 each represent _-CH2NHCOCR1 = _CH2 , _-CH2OH ^or _-CH2OR2 ^. At least two of ^Z1 to ^Z11 are _-CH2NHCOCR1 ⁼ _CH2 .
R ¹ represents -H or -CH ₃ , R ² has 1 carbon number
~4 alkyl group] Melamine group-containing acrylamide compound represented by 30 to 90% by weight (B) Component Organic solvent that dissolves the above (A) component 70 to 10% by weight (C) Component Photosensitizer ( After applying 0.05 to 5% by weight of component A) on paper, drying to remove the organic solvent from the paper, and then embossing the paper, the paper is irradiated with light to contain the melamine group of component (A). A method for producing a process release paper, characterized by photopolymerizing an acrylamide compound.