JPH0455614B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Application Field] The present invention relates to a coated synthetic paper that is capable of printing, writing, and printing, and has good adhesion between the base material and the coating layer, water resistance, blocking resistance, and weather resistance. It is. [Prior Art] Aqueous binders for synthetic paper obtained by coating a polypropylene, polyethylene terephthalate, or polystyrene plastic film with an aqueous coating agent generally include cellulose derivatives such as carboxymethyl cellulose, methyl cellulose, and hydroxyethyl cellulose, and polystyrene. Water-based binders such as acrylic acid and polyacrylic acid amide are known, and a water-based coating agent based on these is applied onto a polypropylene, polyethylene terephthalate, or polystyrene-based plastic film as a base material. It is known in the prior art to form synthetic papers by forming layers. [Problems to be Solved by the Invention] However, the synthetic paper manufactured by the above manufacturing method has problems in the adhesion between the base material plastic film and the coating layer,
Water resistance and blocking resistance were insufficient. One possible solution to this problem is to add a crosslinking agent such as melamine resin or epoxy resin to the thermosetting acrylic resin varnish, but this method requires a heat treatment process, so There is a problem in that the material must be heat resistant.On the other hand, even when other crosslinking agents are used, the physical properties necessary for synthetic paper, such as printability, water resistance, weather resistance, etc. However, the effect of sufficiently improving adhesion and blocking resistance has not yet been achieved. [Means for Solving the Problems] In order to solve the problems of the prior art as described above, the present invention uses a cold-crosslinkable acrylic aqueous emulsion as the main binder, thereby making it possible to print, write, and print. It was created with the aim of providing a synthetic paper that has good adhesion between the base material and the coating layer, and has good water resistance, weather resistance, and blocking resistance, and its composition is made of polypropylene film, polyethylene film, etc. , polyethylene terephthalate film, or polystyrene film as the main binder, (A) component: hydrazine derivative having at least two hydrazine residues (B) component: carbonyl group-containing acrylic copolymer A synthetic paper on which a coating layer is formed of a room-temperature crosslinkable acrylic aqueous emulsion consisting of an aqueous dispersion mainly consisting of aqueous dispersion, wherein the surface layer of the synthetic paper contains an inorganic fine powder, and the surface layer of the synthetic paper contains an inorganic fine powder. is characterized in that it is formed in a coating layer in which the solid content of the surface layer is 50% by weight or more. In the present invention, synthetic paper refers to synthetic paper whose surface layer contains inorganic fine powder in an amount of 50% by weight or more based on the solid content of the surface layer. Next, the present invention will be explained in detail. The type of plastic film that can be used in the present invention is not particularly limited as long as it has a smooth surface. For example, particularly good effects can be obtained by using polypropylene, polyethylene film, polyethylene terephthalate film, and polystyrene film. A plastic film made opaque by matte processing may be used, or a plastic film made by adding an inorganic filler to a film resin and stretching the film to make it opaque may be used. In addition, in the room-temperature crosslinkable aqueous acrylic emulsion as the main binder that can be applied in the present invention, the hydrazine derivative having at least two hydrazine residues as the component (A) is, for example, 2-
Mention may be made of the following dicarboxylic acid dihydrazides containing 10, especially 4 to 6, carbon atoms. Oxalic acid dihydrazide, malonic acid dihydrazide, succinic acid dihydrazide, glutaric acid dihydrazide, adipic acid dihydrazide, sebacic acid dihydrazide, maleic acid dihydrazide, fumaric acid dihydrazide and/or
or itaconic acid dihydrazide, aliphatic water-soluble dihydrazines having 2 to 4 carbon atoms, such as ethylene-1,2-dihydrazine, propylene-1,3-dihydrazine and butylene-1,4-
Dihydrazine. Among these, adipic acid dihydrazide, isophthalic acid dihydrazide, and sebacic acid dihydrazide are preferred. In addition, the acrylic copolymer having a carbonyl group as the component (B) includes, for example, (a) methyl methacrylate, a vinyl aromatic compound,
Monomer selected from tertiary butyl methacrylate, tertiary butyl acrylate, vinyl halide, ethylene 0 to 75% by weight (b) Acrylic or methacrylic acid of an alkanol having 2 to 8 carbon atoms esters, vinyl esters, methyl acrylate, 1,3-
Monomer selected from dienes 99.4-25% by weight (c) Carbonyl group-containing monomer having at least one aldo or keto group and one polymerizable double bond in the molecule 0.1-20% by weight % (d) Mono or/and dicarboxylic acids having 3 to 5 carbon atoms or/and 1 to 5 nitrogen atoms
Amides of these acids substituted by alkyl groups or/and alkylol groups having 4 carbon atoms 0.5-10% by weight Optionally (e) Acrylonitrile, methacrylonitrile 0-40% by weight Above (a) to ( The glass transition point obtained by emulsion polymerization of the vinyl monomer of e) in the above ratio is -80
It is a carbonyl group-containing copolymer with a temperature of ℃ to +70℃. Vinyl monomers of component (a), i.e. methyl methacrylate, vinyl aromatic compounds such as styrene,
Tertiary butyl methacrylate, tertiary butyl acrylate, vinyl halides such as vinyl chloride and/or
Alternatively, vinylidene chloride and ethylene are used in an amount of 0 to 75% by weight, preferably 20 to 50% by weight of the copolymer. As the vinyl monomer of component (b), for example, 2 to 8
Alcohols with 1 carbon atoms such as ethanol, isopropanol, n-propanol, n
- esterified products of butanol, isobutanol or 2-ethylhexanol and acrylic acid and/or methacrylic acid, methyl acrylate,
Examples include vinyl acetate, vinyl propionate, and 1,3-dienes (eg, butadiene). Among these, 2-ethylhexyl acrylate, n-
Butyl acrylate and ethyl acrylate are preferred. These component (b) monomers are 99.4% in the copolymer.
It is used in an amount of ~25% by weight, preferably 80-50% by weight. In addition, as the carbonyl group-containing monomer of component (c), a monomer having at least one aldo group or keto group and one polymerizable double bond in the molecule,
That is, especially polymerizable monoolefinically unsaturated aldo and keto compounds, including ester groups (-COO-) and carboxyl groups (-COOH).
Compounds with only In particular acrolein, diacetone acrylamide, formylstyrene, vinyl alkyl ketones preferably having 4 to 7 carbon atoms, such as in particular vinyl methyl ketone, vinyl ethyl ketone and vinyl isobutyl ketone and/or (In the formula, R ¹ is H or CH ₃ , R ² is H or an alkyl group having 1 to 3 carbon atoms, R ³ is an alkyl group having 1 to 3 carbon atoms, and R ⁴ is 1
acrylic (methacrylic)oxyalkylpropanal, diacetone acrylate, acetonyl acrylate, diacetone acrylate, diacetone methacrylate, 2-hydroxypropyl acrylate-acetyl acetate, meaning an alkyl group having ~4 carbon atoms) and butanediol-1,4-acrylate-acetylacetate are used. Among these, acrolein, diacetone acrylamide, and vinyl methyl ketone are preferred. The carbonyl group-containing monomer as component (c) is used in an amount of 0.1 to 20% by weight, preferably 2 to 7% by weight of the copolymer. Furthermore, the monomer of component (d) is a monoolefinically unsaturated monomer having 3 to 5 carbon atoms.
and/or dicarboxylic acids, such as acrylic acid, methacrylic acid and maleic acid, and/or their amides, such as acrylamide, methacrylamide, and/or their N-alkyl or N-alkylol derivatives, such as N-methylacrylamide, N-isobutyl Examples include acrylamide, N-methylmethacrylamide, N-methylolacrylamide, N-methylolmethacrylamide, N-ethoxymethylacrylamide, N-n-butoxymethylacrylamide, or N-isopropoxymethacrylamide, among which acrylic acid, methacrylamide Preferred acids are itaconic acid and maleic acid. These vinyl monomers as component (d) are
It is used in an amount of 0.5 to 10% by weight, preferably 1 to 5% by weight. If necessary, in addition to these vinyl monomers (a) to (d), acrylonitrile and methacrylonitrile may be added from 0 to
By adding 40% by weight or/and 0.1 to 10% by weight of monoolefinic unsaturated sulfonic acid, the glass transition temperature of the copolymer obtained by emulsion polymerization is -85℃~
Determine the type and amount of each vinyl monomer so that the temperature is +70℃. This aqueous dispersion of the copolymer of component (B) can be prepared by conventional means by copolymerizing the monomers in an aqueous emulsion using conventional emulsifiers and dispersants, and many If the copolymer concentration is 40-60% by weight. As emulsifiers and dispersion aids,
Anionic and/or nonionic emulsifiers are often contained in an amount of 0.2 to 3% by weight, based on the amount of copolymer. An example is below. Sodium dialkyl sulfone succinate, sodium salt of sulfated oils, sodium salt, sodium salt, potassium salt and ammonium alkyl sulfate of alkyl sulfonic acids, alkali metal salts of sulfonic acids, oxyalkylated _C12 - _C24-
alkali metal salts of fatty alcohols and oxyalkylated alkylphenols, as well as other oxyethylated fatty acids, fatty alcohols and/or fatty amides,
Oxylethylated alkylphenols, as well as sodium salts of fatty acids such as sodium stearate and sodium oleate. The glass transition temperature of the copolymer is determined by conventional methods, for example from measurements of the elastic modulus when testing creep as a function of temperature, or using DTA (Differential Thermal Analysis). Such room-temperature crosslinking acrylic aqueous emulsion is available from Mitsubishi Yuka Verdice Co., Ltd. as Acronal.
YJ−2715D, YJ−2716D, YJ−2720D, YJ−
It is sold under the trade names 2740D and YJ-2741D. This main binder contains 50% by weight or more of room-temperature crosslinkable acrylic aqueous emulsion, and a portion (50% by weight or less) of non-crosslinked acrylic aqueous emulsion, SBR latex, ethylene/vinyl acetate. It may be replaced with a copolymer emulsion, an ethylene/vinyl acetate/vinyl chloride copolymer emulsion, or a vinyl acetate/acrylic acid ester copolymer emulsion. This main binder contains solid content of components (A) and (B).
The surface may be roughened by blending 0 to 1000 parts by weight of inorganic fine powder with a powder diameter of 15 μm or less per 100 parts by weight. When used as a coating liquid for the surface layer of synthetic paper, as shown in the examples, the solid content of the room-temperature crosslinking acrylic emulsion in the coating layer after drying is 10 to 50% by weight, and the inorganic fine powder is 90% by weight. ~50
Weight %, preferably 10 to 30 in terms of solid content in the coating layer after drying of the room-temperature crosslinkable acrylic aqueous emulsion
The inorganic fine powder is used in a proportion of 90 to 70% by weight. In addition, when used as an undercoat agent for the surface of synthetic paper, such as a primer, a cold crosslinkable acrylic aqueous emulsion has a solid content of 70 to 70% in the dry coating layer.
It is preferable to use 100% by weight and 30 to 0% by weight of inorganic fine powder. Such inorganic fine powders include pigments such as calcium carbonate, satin white, silica, titanium oxide, alumina, clay, curcum, aluminum sulfate, zinc white, iron oxide, etc., but calcium carbonate is particularly preferred. Further, the particle size of this inorganic fine powder is preferably 15μ or less, particularly preferably 0.1 to 10μ. The reason for this is that if the particle size of the inorganic fine powder is 15 μm or more, the surface of the resulting synthetic paper will be rough and its smoothness will deteriorate. Other organic colorants and fine particles such as polystyrene called plastic pigments may also be added. Further, for the purpose of facilitating coating, a small amount of solvent or the like may be used. In addition, colorants, preservatives,
A flow improver, a wetting agent, a film-forming aid, an antifoaming agent, a plasticizer, etc. may be added to the binder. The coating method in the present invention may be a conventional coating method. The coated plastic film is dried to form a coating layer on the surface of the plastic film base material. The synthetic paper of the present invention contains at least an inorganic fine powder in its surface layer, and the inorganic fine powder may be present in an amount of 50% by weight or more in the solid content of the surface layer. [Operations and Effects of the Invention] The synthetic paper of the present invention is produced by coating a plastic film as a base material with a coating solution containing an aqueous acrylic emulsion that can be crosslinked at room temperature as a main binder, and then crosslinking it at room temperature. , printing, writing,
It is possible to form a strong coating layer with good adhesion between the base material and the coating layer, and excellent water resistance, blocking resistance, and weather resistance. This is because the crosslinking agent, which undergoes a crosslinking reaction at room temperature, is already dispersed in the acrylic emulsion, so when adding an inorganic substance to create a water-based coating agent,
It is extremely easy to mix the synthetic resin, crosslinking agent, and inorganic substance, and the adhesion between the base material and the coating layer is improved due to the crosslinking between the inorganic substance and the synthetic resin and the crosslinking agent, and some interaction with the surface layer of the base material. This is because water resistance is improved. In addition, polymerization through crosslinking acts to prevent adhesion of the coated surface, which is effective in preventing blocking. Furthermore, since a room-temperature crosslinkable acrylic resin aqueous emulsion is used, a heat treatment step, a crosslinking agent addition step, etc. are not necessary, and the effect can be sufficiently exhibited through normal steps. In particular, the synthetic paper of the present invention contains a considerable amount of inorganic fine powder at least in its surface layer, so it has good printing, writing, and printability, and exhibits excellent blocking resistance. . In the present invention, a solvent type or water-based type coating agent may be further applied on top of the coating agent. This is preferable from the standpoint of further improving water resistance, blocking resistance, gloss, and the like. in this case,
Very warm crosslinking type coating agents often dissolve and peel off due to the solvent in the top coat, but the present invention exhibits excellent water resistance. Naturally, a method of overcoating after printing may also be adopted. [Example] Hereinafter, the present invention will be explained in more detail with reference to Examples. Note that parts and percentages in the examples are based on weight unless otherwise specified. Example 1 The following raw materials were charged into a reaction vessel equipped with a temperature controller, an anchor stirrer, a reflux condenser, a supply vessel, a thermometer, and a nitrogen inlet tube. 200 parts of water 35% aqueous solution of the sodium salt of the sulfuric acid half ester of p-nonylphenol (anionic emulsifier) reacted with 20 moles of ethylene oxide 5 parts of p-nonylphenol (nonionic emulsifier) reacted with 25 moles of ethylene oxide 20% solution
20 parts The following mixture was used as a feed. 200 parts of water 25 parts of a 35% solution of the anionic emulsifier described above
A 2.5 part solution was prepared. After purging the inside of the reactor with nitrogen gas, 10% of the feed was added to the charge and the mixture was heated to 90°C. 10% of the feed was then injected into the reactor, and then the remaining feed was fed into the reactor evenly in parallel over a period of 3 to 3.5 hours. After supply
After being held at 90°C for 1.5 hours, the reactor was cooled to room temperature. The pH of the dispersion was adjusted to 7 to 8 with aqueous ammonia, and 8 parts of adipic acid dihydrazide was added to bring the pH to about 1.
Stir for hours. In this way, an aqueous dispersion with a solid content of 50% was obtained. Example 2, Example 3 In the production example of Example 1, the copolymerization composition was changed to the ratio shown in Table 1, and the same polymerization operation as in Example 1 was performed to obtain an aqueous dispersion. Example 4 An aqueous dispersion was obtained by carrying out the same polymerization operation as in Example 1 except that the copolymerization composition was changed to the ratio shown in Table 1 and the hydrazine derivative was not added.

【table】

[Table] Example 1 A composition of the following formulation-1 was applied as a primer to a corona discharge-treated polypropylene film having a thickness of 60μ, and dried at 100°C for 60 seconds in a dryer. The thickness of the coating layer after drying was 5μ. A composition of the following formulation-2 was applied to this product and dried in a dryer at 100°C for 60 seconds. The thickness of the coating layer after drying was 25μ. The following tests were conducted on the synthetic paper thus obtained. In other words, regarding the adhesion between the base material and the coating layer, we evaluated the peeling state of the coating layer by attaching Nichiban Co., Ltd.'s adhesive cellophane tape to the sample and peeling it off all at once. For water resistance, evaluate the peeling condition of the surface by soaking it in water for a certain period of time and then rubbing it with your hands.For blocking resistance, put the coated surfaces of the samples on top of each other and apply a surface pressure of 100g/cm. ^2. It was maintained at 40°C for 24 hours, and after cooling, it was evaluated whether blocking occurred. The results of the above test showed that the adhesion, water resistance, and blocking resistance between the base film and the coating layer were extremely good. Formulation-1 (Dry weight parts) Room temperature cross-linked acrylic emulsion Production example 1 40 Formulation-2 (Dry weight parts) Emulsion Production example 1 30 Production example 2 10 Calcium carbonate with particle size of 1.8μ 100 Titanium White 50 Dispersant 0.5 Dispersion aid 0.5 Example 2 The composition of the following formulation was coated on a polyethylene terephthalate film with a thickness of 50μ and dried in a dryer to obtain synthetic paper with a coating layer thickness of 20μ . The synthetic paper thus obtained had extremely good adhesion between the base material and the coating layer, water resistance, and blocking resistance. The testing methods for the adhesion, water resistance and blocking resistance were the same as in Example 1 above. Formulation (parts by dry weight) Room-temperature crosslinkable acrylic emulsion Production example 3 26 Production example 2 8 Silica powder 20 Titanium white 30 Dispersant 0.5 Comparative example 1 In Example 2, polypropylene film and polyethylene terephthalate film were used instead of polyethylene terephthalate film. A coated synthetic paper was obtained in the same manner except that 34 parts by weight (dry weight) of the non-crosslinked acrylic emulsion obtained in Production Example 4 was used instead of 34 parts by weight of the room-temperature crosslinkable acrylic emulsion. The coating layer of this coated synthetic paper had poor water resistance and adhesion to the base layer. Example 3 Formula-1 of Example 1 was used as a primer, and
For the top coat, (parts by dry weight) Room-temperature cross-linking acrylic emulsion Production example 1 20 Very-temperature cross-linking acrylic emulsion 20 Acronal YJ-3031D manufactured by Mitsubishi Yuka Verdice Co., Ltd. Film forming temperature 15°C Solid content 48% Calcium carbonate 100 Coated paper was obtained in the same manner as in Example 1, except that titanium white 50 dispersant (sodium tripolyphosphate) 0.5 antifoaming agent (San Nopco SN-DF-113) 0.1 was used. This coated paper had good adhesion, water resistance, and blocking resistance. Example 4 (Dry weight parts) Room-temperature cross-linking acrylic emulsion 26 Mitsubishi Yuka Verdice Co., Ltd. Acronal YJ-2716D Very-temperature cross-linking acrylic emulsion 20 Mitsubishi Yuka Verdice Ltd. Acronal YJ-2800D Silica powder 20 Titanium white 30 Dispersion Agent (sodium tripolyphosphate) 0.5 Plasticizer BBP 5 Antifoaming agent SN-DF-113 0.1 Coating agent with the above composition was applied directly to the surface of a polypropylene film treated with corona discharge so that a coating layer with a thickness of 30μ was obtained. Coated paper was obtained by drying at 100°C for 60 seconds. This product had good blocking resistance, water resistance, and adhesion of the coating layer to the substrate. Example 5 The composition of Formulation 1 of Example 1 was applied as a primer to a corona discharge-treated polypropylene film having a thickness of 60 μm, and the film was dried in a dryer at 100° C. for 60 seconds. The thickness of the coating layer after drying was 5μ.
This material was coated with the composition of the following formulation-3, and immediately immersed in water at 20°C for 60 seconds to coagulate the coating agent, and the solvent in the coagulated layer was removed into water. After drying, dry at 100℃ for 60 seconds to determine the coating thickness.
A 30μ coated paper was obtained. This coated paper had extremely good adhesion, water resistance, and blocking resistance. Formulation-3 (Dry weight parts) Vinyl chloride/vinyl acetate copolymer resin 70 Dimethylformamide 200 Clay 20 Titanium white 20 Calcium carbonate 140 Dispersant (sodium tripolyphosphate) 0.5 Plasticizer (DBP) 10 Example 6 Example 5 A coating agent having the composition of the following formulation-4 was applied to primer-coated paper and heat-treated at 130°C for 120 seconds. This product had good adhesion and water resistance, and also showed no problems in blocking resistance at 50° C. and 300 g/cm ² pressure. Formulation-4 (Dry weight parts) Very-temperature crosslinking type/thermal crosslinking type acrylic emulsion 50 Acronal S-886S manufactured by Mitsubishi Yuka Verdice Co., Ltd. (Solid content 50%, PH3.5) Calcium carbonate 100 Titanium white 50 Dispersant 0.5 Foaming agent 0.1

Claims (1)

[Scope of Claims] 1. On the surface of a plastic film such as polypropylene film, polyethylene film, polyethylene terephthalate film, or polystyrene film, as a main binder, (A) component: a hydrazine derivative having at least two hydrazine residues; Component (B): Synthetic paper on which a coating layer is formed using a room-temperature crosslinkable acrylic aqueous emulsion consisting of an aqueous dispersion containing a carbonyl group-containing acrylic copolymer as a main component, the surface layer of the synthetic paper comprising: 1. A synthetic paper comprising a coating layer containing an inorganic fine powder, the inorganic fine powder accounting for 50% by weight or more of the solid content of the surface layer. 2. The synthetic paper according to claim 1, wherein component (A) is blended in a ratio of 0.02 to 1 mole per mole of carbonyl groups in the carbonyl group-containing copolymer of component (B). 3. The main binder contains inorganic fine powder in a proportion of 0 to 1000 parts by weight based on 100 parts by weight of the copolymer of components (A) and (B). synthetic paper.