JPS6212277B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to an adhesive for synthetic resin films, and more particularly to an adhesive for synthetic resin films suitable for bonding synthetic resin films onto base materials such as metal, paper, synthetic resin, and wood. 2. Description of the Related Art It is a common practice to bond a synthetic resin film to an object made of metal, paper, synthetic resin, wood, or the like to impart properties such as waterproofness and aesthetic appearance to the object. However, conventionally, such adhesive processing has had problems in that the film undergoes natural shrinkage or heat shrinkage, resulting in defects in the product, or that the film peels off when the object to which the film is bonded is bent. Therefore, it is an object of the present invention to solve the above-mentioned problems in the conventional bonding process, to eliminate film peeling due to film shrinkage or bending, and to achieve superior gloss and thickness compared to conventional adhesive processes. An object of the present invention is to provide an adhesive for synthetic resin film that gives an adhesive processed product with a sense of volume. The adhesive for synthetic resin film according to the present invention includes (i)
formula (wherein R ¹ is H or CH ₃ and R ² is H or an alkyl group) or an ester thereof; (In the formula, R ³ is H or CH ₃ and R ⁴ is an alkylene group. consisting of an oligomer with a hydroxyl value of 50 to 400 and (ii) a polyfunctional polyisocyanate,
The oligomer (i) and the polyfunctional isocyanate
The composition ratio with (ii) is 0.5 to 1.5 reaction equivalents of polyfunctional isocyanate per equivalent of hydroxyl group of the oligomer. This synthetic resin film adhesive is made of polyvinyl chloride resin, polyester resin, polyamide resin,
Suitable for bonding various synthetic resin films such as polystyrene resin, polyacrylic resin, polyethylene resin, and polypropylene resin onto objects made of metal, paper, wood, synthetic resin, glass, rubber, etc. The adhesive of the present invention is particularly effective when bonding films that are relatively easily attacked by solvents, such as polyvinyl chloride films, which have been a problem in the past. By using the adhesive of the present invention, it is possible to obtain a strong composite material that does not suffer from film shrinkage or film peeling due to bending of the object, and at the same time has an aesthetic appearance that is not seen with conventional adhesives - extremely high gloss and A significantly superior feeling of fleshiness (volume) is provided when a transparent film is attached. The oligomer (i) mentioned above that is blended into the adhesive for synthetic resin films of the present invention contains acrylic acid or methacrylic acid or an ester thereof of the formula [] and a hydroxyalkyl ester of acrylic acid or methacrylic acid of the formula []. Polymerized or containing 80% by weight or more of these as monomer units,
Other vinyl monomers copolymerizable with these monomers, such as vinyl acetate, vinyl propionate, vinyl versatate, vinyl chloride, vinylidene chloride, styrene, α-methylstyrene, acrylonitrile, ethylene, propylene, acrylamide, methacrylamide, N - Oligomers containing 20% by weight or less of methylolmethacrylamide, butadiene, itaconic acid, methyl vinyl ether, diallyl phthalate, and mixtures thereof as monomer units. As the compound of the above formula [], in the formula, R ² is H
Or a linear or branched alkyl group having 1 to 8 carbon atoms is preferable, and examples of such compounds include acrylic acid, methyl acrylate, ethyl acrylate, propyl acrylate, butyl acrylate, and acrylic acid. Pentyl, hexyl acrylate, heptyl acrylate, octyl acrylate, methacrylic acid, methyl methacrylate, ethyl methacrylate, propyl methacrylate, butyl methacrylate, pentyl methacrylate, hexyl methacrylate, heptyl methacrylate, octyl methacrylate, and Any mixture of these can be mentioned. As for the compound of the above formula [], R ⁴ in the formula is preferably a linear or branched alkylene group having 1 to 6 carbon atoms, and examples of such compounds include hydroxymethyl ester, hydroxyethyl ester, and hydroxyl of acrylic acid. propyl esters, hydroxybutyl esters, hydroxypentyl esters and hydroxyhexyl esters, and hydroxymethyl esters, hydroxyethyl esters, hydroxypropyl esters, hydroxypentyl esters and hydroxyhexyl esters of methacrylic acid, and any mixtures thereof. These monomers can be copolymerized using any conventionally known polymerization method, such as bulk polymerization, suspension polymerization, or solution polymerization, under normal pressure or under increased pressure. Number average molecular weight of oligomer (i) (vapor pressure osmosis method)
Vapor Pressure Osmometry Method) is approximately 300
~ up to about 10,000, preferably within the range of 300-5,000. If the number average molecular weight of the oligomer is less than 300, the monomer odor will be strong, causing some problems in use, and the adhesive strength before and after curing will be insufficient, and if the number average molecular weight exceeds 10,000, the viscosity of the composition will become high. This is undesirable because fluidity decreases, causing problems in workability during the coating process, and requiring the use of a large amount of solvent for dilution.
It is also undesirable because it becomes difficult to "wet" with the base material, resulting in a hard and brittle adhesive. The composition ratio of the monomers [] and [] is such that the hydroxyl value of the resulting copolymer is 50 to 400, preferably 50.
-250 range. When the hydroxyl value of the oligomer (i) is less than 50, the cohesive force is extremely poor and the desired adhesive force cannot be obtained. Moreover, if the hydroxyl value exceeds 400, a large amount of isocyanate will be used, which is not preferable because not only will the weather resistance be poor, but the adhesive will be hard and brittle, resulting in poor workability. The oligomer (i) also includes a blend of an oligomer or polymer without a hydroxyl group and an oligomer or polymer having a hydroxyl group so that the hydroxyl value of the blend falls within the above range. The hydroxyl value can be measured according to JIS 3342 (1961) (acetic anhydride-pyridine method). Examples of the polyfunctional isocyanate to be blended with the oligomer (i) in the adhesive for synthetic resin films of the present invention include tolylene diisocyanate and its hydrogenated products and adducts, triphenylmethane triisocyanate, methylene bis-di-phenyl Isocyanate and its hydrogenated product, hexamethylene diisocyanate, xylene diisocyanate and its hydrogenated product, 4,4'-dicyclohexylmethane diisocyanate, isophorone diisocyanate, dianisidine diisocyanate, tridene diisocyanate, metaxylylene diisocyanate, triallylisocyanurate, and Examples include arbitrary mixtures of these. These polyfunctional isocyanates are preferably used in an amount of 0.5 to 1 equivalent of hydroxyl group in the oligomer (i).
It is blended at a ratio of 1.5 reaction equivalents. If the amount of polyfunctional isocyanate is less than 0.5 reaction equivalent, the adhesive will remain sticky for a long time, causing transfer and contamination to the base material, which is undesirable.On the other hand, if it exceeds 1.5 reaction equivalent, the adhesive will become hard. and the adhesive strength is poor.
It is undesirable because it has low bending strength and extremely poor workability. In addition to the polyfunctional isocyanate, an amino resin may be added to the adhesive of the present invention, if necessary. Such amino resins include, for example, etherified methylolmelamine resins such as methylated methylolmelamine, ethylated methylolmelamine, butylated methylolmelamine, isopropylated methylolmelamine; methylated methylolurea, ethylated methylolurea, butylated methylolurea; etherified methylolurea resins such as; and methylated methylolurea melamines,
Examples include etherified urea/melamine cocondensates such as ethylated methylol urea melamine and butylated methylol urea melamine. The adhesive for synthetic resin films according to the present invention can be prepared by mixing the oligomer (i) and a polyfunctional isocyanate using a conventionally known general mixing method. In addition to the above-mentioned copolymer and polyfunctional isocyanate, the adhesive for synthetic resin film of the present invention includes:
A curing catalyst is generally included. As the curing catalyst to be added to the adhesive of the present invention, catalysts commonly used to promote the reaction of isocyanates can be used. Typical curing catalysts used in the present invention include amines such as trimethylamine, triethylamine, tripropylamine, tributylamine, phenylamine, triethylenediamine; metal compounds such as stannath octoate, dibutyltin di-2-ethyhexoate, dibutyl Chindilaurate, Red-2-ethylene hexoate, Sodium-0-phenyl phenate, Potassium oleate, Bismuth nitrate,
These include tetra(2-ethylhexyl) titanate, stannic chloride, ferric chloride, iron 2-ethylhexoate, cobalt 2-ethylhexoate, zinc naphthenate, and antimony trichloride. The amount of these catalysts used is 2% by weight or less, preferably 10 ppm to 1% by weight, based on the total resin components. The adhesive for synthetic resin films of the present invention may further contain xylene, butanol, ethyl acetate,
Methyl ethyl ketone, methyl isobutyl ketone,
Solvents such as paint thinner; Pigments such as titanium white, lead white, zinc white, aluminum powder, red iron, ocher, Pallas, Lysol, and Bold; Phthalate esters,
Plasticizers such as phosphoric acid esters, epoxidized vegetable oils, polyesters, and epoxys; Stabilizers such as lead salts, metal soaps, organic tins, and epoxy compounds; amines, phenols, phosphorous acid derivatives,
Antioxidants such as sulfur compounds; ultraviolet absorbers such as phenyl salicylate type, benzophenone type, and benzotriazole type; etc. can be blended. These additives can be blended in conventional general amounts. The adhesive of the present invention can be applied using a spreader method using a doctor knife, a roll coater method using a roll, a brush coater method, a spray coater method, a dip coater method, or the like. The adhesive containing the polyfunctional isocyanate of the present invention is generally cured at a temperature of 0 to 100°C after application. The curing time depends on the curing temperature, catalyst, etc., but is usually 50 hours or less, preferably about 3 seconds to 8 hours. If the adhesive for synthetic resin film according to the present invention is used, the synthetic resin film can be attached to a base object such as metal, paper, synthetic resin, or wood without causing peeling of the film due to shrinkage of the film or bending of the object. As mentioned above, the composite material can be adhesively processed, and the aesthetic appearance of the resulting composite material is significantly improved compared to conventional products.In addition, the following features are also recognized. (1) An adhesive with a high solid content concentration and low viscosity can be obtained, and the amount of solvent used can be reduced, which is advantageous in terms of resource conservation and pollution control. (2) High fluidity, good leveling properties, and good "wetting" of adherends. (3) The amount of coating may be as small as 1 to 5 g/m ² . (4) Good void filling properties. (5) In the case of plasticized films, there is no aging of plasticization caused by plasticizers. (6) Even if the film is sensitive to heat, it will not shrink even if it is heated after complete adhesion. Examples of the present invention will be described below. Example 1 Synthesis of oligomer A reaction apparatus equipped with a dropping device, a stirrer, a thermometer, and a reflux condenser was charged with the solvent and degree of polymerization regulator shown in Table 1, and the temperature was raised to the respective reaction temperature while stirring. Ta. After the temperature rise is completed, about 40% of the monomer mixture and radical generator shown in Table 1 are added from the dropping device.
The mixture was continuously added dropwise over a period of time, and after completion of the dropwise addition, the reaction was further continued at the same temperature for 2 hours. The obtained oligomer solution was concentrated in vacuo to obtain an oligomer with a solid content of 98%. In this way, nine types of oligomers shown in Table 1 were prepared. The abbreviations in the monomer compositions in Table 1 are as follows. AA...acrylic acid, EA...ethyl acrylate,
MA...methyl acrylate, BA...butyl acrylate, i-BA...isobutyl acrylate, 2EHA...
2-ethylhexyl acrylate, 2HEA...2-hydroxyethyl acrylate, MMA...methyl methacrylate, 2HEMA...2-hydroxyethyl methacrylate, MAL...lauryl methacrylate,
HPMA…Hydroxypropyl methacrylate,
VAC...Vinyl acetate.

[Table] Example 2 Preparation of adhesive for synthetic resin film Oligomers No. 1 to No. 9 obtained in Example 1 were combined with polyfunctional isocyanate and OH/NCO shown in Table 2, respectively.
= 1/1, coating materials A to L
was prepared. In Table 2, Duuranate 12A
-90CX is a hexamethylene diisocyanate adduct (volatile content 10%) manufactured by Asahi Kasei Co., Ltd., Coronate L and HL are tolylene diisocyanate and hexamethylene diisocyanate (both volatile content 25%) manufactured by Nippon Polyurethane Co., Ltd., respectively, and Takenate D-120N is hydrogenated xylylene diisocyanate (volatile content 25%) manufactured by Takeda Pharmaceutical Co., Ltd. The resin concentration and viscosity of the compounded adhesive were measured and shown in Table 2.

【table】

[Table] Example 3 Adhesive performance test Thickness 2 for cosmetic boxes laminated with aluminum
The adhesive prepared in Example 2 was individually applied to the surface of 2 mm thick paperboard using a roll to a solid content of 2 g/m ² , a 30 μ soft vinyl chloride film was laminated thereon, and the adhesive was left at room temperature for 48 hours. Adhesive peel strength and blocking properties were measured for the sample and the sample that had been heated at 50°C for 8 hours and then cured for 24 hours, and the gloss and volume were visually judged. The results are shown in Table 3. In addition, both gloss and volume were judged using a 5-stage method: excellent (◎), good (〇), fair (△), slightly poor (x), and poor (XX), and the adhesive peel strength was
According to JIS K-6854-1977 (180° peel strength g/
15 mm and a tensile speed of 200 mm/min), and the blocking property was measured according to JIS-K-6842-1977.

[Table] Example 4 Shrinkage test of adhesive film 10 cm from the composite obtained in Example 3 (left at room temperature for 48 hours)
Cut out 10cm test pieces and heat them at 80℃
The bonded film was heated in a hot air dryer under the conditions of 2 hours, 80°C x 10 hours, and 50°C x 72 hours, and the amount of shrinkage of the bonded film was measured. The results are shown in Table 4.

[Table] Example 5 Bending test of adhesive film The adhesive prepared in Example 2 and commercially available products MN and O (see Table 3) were each applied to an aluminum plate with a thickness of 0.3 mm using a roll to a solid content of 3 g/ ^m2. , this has 30
A μ soft vinyl chloride film was attached. After 2 and 7 days of being left at room temperature, make a cut in the outer film layer with a razor blade, align the cut with the bending direction, place it on a round bar of 5, 10, 20, 30, and 60 mmφ, and place the test piece on the outer periphery of the bar. Then, momentarily bend it to 180°,
Peeling and spreading of the cut at that time was investigated. Table 5 shows the diameters of the round bars in which peeling or spreading was observed. The smaller the outer diameter of the round rod that is wrapped around it, the stronger it can withstand severe bending and the stronger the adhesive force.

【table】

[Table] Example 6 Peeling strength when various films are adhered to aluminum foil and steel plate 50 μ thick aluminum foil and 0.5 mm thick
The adhesive prepared in Example 2 was applied to a JIS G 3141 steel plate with a roll to a solid content of 3 g/m ² , and the following five types of synthetic resin films were laminated thereon. JIS-K- peel strength after leaving these at room temperature for 7 days
Measured in accordance with 6854 (1977). The results are shown in Table 6. Synthetic resin film (a) PVC...30μ thick soft vinyl chloride film (b) Polyester...15μ thick polyethylene glycol terephthalate film (corona discharge treatment) (c) Polypropylene...20μ thick polypropylene film (corona discharge treatment) (d) Polyethylene...30μ Thick soft polyethylene film (e) Nylon...20μ thick nylon-6 film (corona discharge treatment)

【table】

Claims (1)

[Claims] 1 (i) Formula (wherein R ¹ is H or CH ₃ and R ² is H or an alkyl group) or an ester thereof; (In the formula, R ³ is H or CH ₃ and R ⁴ is an alkylene group. consisting of an oligomer with a hydroxyl value of 50 to 400 and (ii) a polyfunctional polyisocyanate,
The oligomer (i) and the polyfunctional isocyanate
An adhesive for synthetic resin films having a composition ratio of (ii) of 0.5 to 1.5 reaction equivalents of polyfunctional isocyanate per equivalent of hydroxyl group of the oligomer. 2. The adhesive according to claim 1, wherein R ² in the compound of the formula [] is H or an alkyl group having 1 to 8 carbon atoms. 3 Claim 1 in which R ⁴ is an alkylene group having 1 to 6 carbon atoms in the compound of the formula []
The adhesive according to item 1 or 2. 4 The oligomer (i) is vinyl acetate, vinyl propionate, vinyl versatile acid, vinyl chloride,
Vinylidene chloride, styrene, α-methylstyrene, acrylonitrile, ethylene, propylene acrylamide, methacrylamide, N-methyl-
Claims 1 to 3 which contain, as a monomer unit, 20% by weight or less of at least one copolymerizable monomer selected from the group of methacrylamide, butadiene itaconic acid, methyl vinyl ether, and diallyl phthalate. Adhesive described in Crab. 5. The polyfunctional isocyanate is tolylene diisocyanate, hydrogenated products and adducts thereof,
Triphenylmethane triisocyanate, methylene bis-diphenyl isocyanate and its hydrogenated product, hexamethylene diisocyanate, xylene diisocyanate and its hydrogenated product 4,4'-
Claims 1 to 4 are at least one selected from the group of dicyclohexylmethane diisocyanate, isophorone diisocyanate, dianisidine diisocyanate, tridene diisocyanate, metaxylylene diisocyanate, and triallylisocyanurate. adhesive. 6. The adhesive according to any one of claims 1 to 5, wherein the synthetic resin film is a polyvinyl chloride film.