JPS6112938B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention is a synthetic resin film composite emulsion coating whose main component is a copolymer aqueous emulsion that has excellent mechanical stability, especially when diluted, and has significantly improved adhesion to synthetic resin films with low polarity. Regarding drugs. In recent years, synthetic resin films have been used for many purposes. As the uses of the film expand, the required performance also becomes more diverse. Composite films are also often used, which are made by laminating a synthetic resin film with other films, paper, aluminum foil, or other base materials, or by coating the film with a gas-barrier coating agent. However, synthetic resin films, especially polyolefin films, have low polarity and poor adhesion, so they have had various problems as substrates for composite films. Therefore, it is desired to develop a laminating adhesive that strongly adheres to synthetic resin films such as polyolefin film, and an anchor coating agent that strongly adheres gas barrier coating agents to synthetic resin films. There has been a strong demand for a water-based emulsion-type coating agent for synthetic resin film composites that combines these characteristics, as well as issues of toxicity, fire risk, and solvent recovery. Such coating agents are often applied onto the film using a gravure roll coater or an air knife coater, but in this case, the amount applied must be extremely small, 0.1 to 1 g/ ^m2 , so the solid content It is also diluted to around 10% by weight. Therefore, shearing is applied in a diluted state. In a synthetic resin aqueous emulsion, the synthetic resin particles are usually protected by an emulsifier and stably dispersed in water, but when the emulsion is diluted with water, the emulsifier that protects the synthetic resin particles is also diluted. As a result, the synthetic resin particles become unstable and their mechanical stability is significantly reduced. Therefore, such coating agents are required to have excellent mechanical stability, especially when diluted. In addition, because the emulsifier contained in conventional emulsion coating agents is hydrophilic, there are problems with low adhesion to synthetic resin films with low polarity and low water resistance. Improvement is also often required. However, there has not yet been an aqueous emulsion coating agent for synthetic resin film composites that has such properties. As a result of repeated research to solve these problems, the present inventors completed the present invention and solved all the problems. That is, the present invention uses 100 parts by weight of a mixed monomer consisting of 80 to 99.9% by weight of an ethylenically unsaturated monomer having no functional group and 0.1 to 20% by weight of an ethylenically unsaturated monomer having a functional group. , a sulfonate copolymerizable emulsifier of an unsaturated dicarboxylic acid derivative, and an aqueous medium together with 0.1 to 10 parts by weight of one or more copolymerizable emulsifiers selected from sulfonate copolymerizable emulsifiers containing an allyl group or methallyl group. This is an aqueous emulsion coating agent for synthetic resin film composites whose main component is an aqueous copolymer emulsion obtained by emulsion polymerization in a synthetic resin film. Furthermore, an aqueous emulsion coating agent for synthetic resin film composites, which is a copolymer aqueous emulsion with an adhesion promoting catalyst added thereto, has particularly excellent water-resistant adhesive strength. The characteristic feature of the aqueous emulsion coating agent for synthetic resin film composites of the present invention is that the emulsifier used in the production of the copolymer aqueous emulsion, which is the main component, is a copolymerizable emulsifier based on a sulfonate of an unsaturated dicarboxylic acid derivative, an allyl The purpose of the present invention is to use one or more copolymerizable emulsifiers selected from sulfonate-based copolymerizable emulsifiers containing groups or methallyl groups. Such an emulsifier is copolymerized with the ethylenically unsaturated monomer during emulsion copolymerization. Therefore,
This emulsifier is present in the copolymer particles in an aqueous copolymer emulsion and stabilizes the copolymer particles. Therefore, unlike surfactants and water-soluble polymer protective colloids used in ordinary emulsifiers, which are stabilized by adsorbing to the surface of copolymer particles, it is difficult to dilute the aqueous copolymer emulsion. Since the emulsifier is not liberated even when diluted, the aqueous copolymer emulsion exhibits excellent mechanical stability. Moreover, by using such a copolymerizable emulsifier, not only does it exhibit excellent water resistance without deterioration in water resistance caused by the emulsifier, but also
In particular, it exhibits excellent adhesion to synthetic resin films such as polyolefin films with low polarity. Ethylenically unsaturated monomers without functional groups used in the present invention include vinyl acetate, vinyl propionate, vinyl laurate, vinyl stearate, vinyl carboxylate branched at the α-position [vinyl pivalate, Beoba (product name of Ciel Chemical Co., Ltd.)
vinyl esters such as methyl acrylate, ethyl acrylate, butyl acrylate, isobutyl acrylate, 2-ethylhexyl acrylate, lauryl acrylate; methyl methacrylate, ethyl methacrylate, methacrylic acid Methacrylic acid esters such as butyl, isobutyl methacrylate, 2-ethylhexyl methacrylate, and lauryl methacrylate; unsaturated carboxylic acid esters other than those listed above, such as methyl crotonate, ethyl crotonate, dibutyl maleate, and diethyl fumarate; One or more of saturated polyhydric carboxylic acid esters; acrylonitrile, methacrylonitrile; styrene, methylstyrene, chlorostyrene; vinyl chloride, vinylidene chloride; and ethylene. Ethylenically unsaturated monomers having functional groups used in the present invention include acrylic acid, methacrylic acid, crotonic acid, maleic acid, fumaric acid, itaconic acid, maleic anhydride, maleic acid monoester, and fumaric acid monoester. Unsaturated carboxylic acids or unsaturated polycarboxylic acid derivatives such as esters; Unsaturated carboxylic acid amides such as acrylamide and methacrylamide; N- such as N-methylol acrylamide and N-methylol methacrylamide;
Methylol unsaturated carboxylic acid amides; unsaturated glycidyl compounds such as glycidyl acrylate and glycidyl methacrylate; alkylolated unsaturated compounds such as hydroxyethyl acrylate, hydroxypropyl methacrylate, and hydroxy vinyl ether; divinyl such as diallyl phthalate and divinylbenzene. or one or more types of diallyl compounds. The ethylenically unsaturated monomer without a functional group and the ethylenically unsaturated monomer with a functional group are appropriately selected and used depending on the type of synthetic resin film used and the type of composite base material. . The proportion used is 80% ethylenically unsaturated monomer without functional groups.
~99.9% by weight and 0.1-20% by weight of ethylenically unsaturated monomers having functional groups. If the amount of ethylenically unsaturated monomers having a functional group is less than 0.1% by weight, reaction or crosslinking due to the functional group will not be sufficient, and if it exceeds 20% by weight, adhesive strength or water resistance will be reduced due to free functional groups that do not participate in reaction or crosslinking. This is not preferable because the properties and other properties are significantly reduced. The sulfonate-based copolymerizable emulsifier of an unsaturated dicarboxylic acid derivative used in the present invention is a compound obtained by adding an alkali metal salt, ammonium salt, or amine base of sulfonic acid to a derivative of an unsaturated dicarboxylic acid. The sulfonate-based copolymerizable emulsifier containing a group or a methallyl group is an allyl group obtained by reacting a diester of an unsaturated dicarboxylic acid containing at least one allyl group or a methallyl group with a sulfite. or methallyl group-containing sulfonate salts. These copolymerizable emulsifiers can be used alone or in combination of two or more. Use of these copolymerizable emulsifiers is preferred because the aqueous copolymer emulsion has better mechanical stability. The amount of these copolymerizable emulsifiers used is 0.1 to 10 parts by weight based on 100 parts by weight of the mixed monomers.
If the copolymerizable emulsifier is less than 0.1 part by weight, the resulting aqueous emulsion coating agent for synthetic resin film composites will not have sufficient mechanical stability, and
If the amount exceeds 1 part by weight, the adhesive strength or water resistance will drop significantly due to an increase in the number of hydrophilic groups, which is undesirable. Further, the aqueous emulsion coating agent for synthetic resin film composites of the present invention can contain an adhesion promoting catalyst. Examples of adhesion promoting catalysts include para-toluenesulfonic acid, oxalic acid, citric acid, ammonium nitrate, ammonium chloride, titanyl sulfate, and titanyl chloride, which sufficiently promote the reaction or crosslinking of functional groups in the aqueous copolymer emulsion. Water-resistant adhesive strength can be improved. The amount of adhesion promoting catalyst used is 20% by weight of the aqueous emulsion coating agent for synthetic resin film composites.
It is as follows. If it exceeds 20% by weight, the adhesive strength to synthetic resin films will be significantly reduced. The copolymer aqueous emulsion, which is the main component of the aqueous coating agent for synthetic resin film composites of the present invention, uses the above-mentioned copolymerizable emulsifier, a radical polymerization initiator, a PH regulator, and, if necessary, a polymerization chain transfer agent. It can be obtained by emulsion copolymerization of the ethylenically unsaturated monomer having no functional group and the ethylenically unsaturated monomer having the aforementioned functional group in an aqueous phase in the presence of an agent. The polymerization method may be either a batch polymerization method or a continuous polymerization method. The polymerization reaction temperature is usually in the range of 30 to 90°C. The radical polymerization initiator is a water-soluble radical polymerization initiator used in normal emulsion polymerization, such as hydrogen peroxide, potassium persulfate, sodium persulfate, ammonium persulfate, butyl hydroperoxide, etc., alone or in combination with l-ascorbic acid, sulfite, etc. Redox systems are used that combine reducing agents such as salts, Rongalites, and ferrous sulfate. As the pH adjuster, acids such as hydrochloric acid, phosphoric acid, acetic acid, succinic acid, boric acid, and carbonic acid, and their salts, and bases such as alkali metal hydroxides, aqueous ammonia, and amines are used. As the polymerization chain transfer agent, mercaptan, carbon tetrachloride, chloroform, etc. can be used as necessary. As the emulsifier, a nonionic surfactant, anionic surfactant, protective colloid, etc. can be used in combination with the above-mentioned copolymerizable emulsifier, but it goes without saying that the use of a large amount is not allowed. In particular, surfactants have the effect of improving the wetting of the aqueous emulsion coating agent for synthetic resin film composites onto the film, and can be added later, but it is also preferable to use them together as emulsifiers. For the aqueous emulsion coating agent for synthetic resin film composites of the present invention, the aqueous copolymer emulsion obtained by the above-mentioned method can be used as it is, but the aqueous copolymer emulsion may be added with a wetting modifier or the like. Additives such as antifoaming agents, viscosity modifiers, fillers, preservatives, freeze stabilizers, film forming aids, plasticizers, and tackifiers may be added as necessary. The aqueous emulsion coating agent for synthetic resin film composites of the present invention not only exhibits excellent mechanical stability even when diluted, but also has high water resistance and exhibits excellent adhesion to polyolefin films. The aqueous emulsion coating agent for synthetic resin film composites of the present invention, which has such excellent properties, can be diluted with water and coated on a film without impairing workability. It can be applied with an extremely small coating amount of ² to form an extremely thin coating film with excellent adhesion. Such an effect is an excellent effect that cannot be expected from various known aqueous coating agents for synthetic resin films. The aqueous emulsion coating agent for synthetic resin film composites of the present invention can be used as an adhesive for laminating synthetic resin films. Furthermore, it can be used as an anchor coating agent for applying a gas barrier coating agent, a coating agent for heat sealing, etc. to a synthetic resin film. It can also be used as a non-coating agent for applying adhesives to synthetic resin films. Furthermore, it can also be used as a binder for coating synthetic resin films with antifogging agents, ultraviolet absorbers, coloring agents, and the like. As described above, it should be understood that in this specification, the aqueous emulsion coating agent for synthetic resin film composites is used to collectively refer to coating materials and adhesives for synthetic resin films, as well as anchor coating agents. . The synthetic resin film may be coated with the aqueous emulsion coating agent for synthetic resin film composites of the present invention by a known method using a gravure roll coater, an air knife coater, or the like. EXAMPLES Hereinafter, the present invention will be explained with reference to Examples, but is not limited thereto. Example 1 In a reaction vessel equipped with a stirrer, a reflux condenser, and a thermometer, 150 parts by weight of water, 0.5 parts by weight of sodium acetate, and the following chemical formula as an emulsifier were added: 1.5 parts by weight of a copolymerizable emulsifier having an allyl group and a sulfonic acid group represented by the formula were added, and then the following composition was prepared: 2-ethylhexyl acrylate 55 parts methyl methacrylate 37 parts acrylic acid 4 parts N-methylolacrylamide 4 parts by weight Add 100 parts by weight of mixed monomers, stir to emulsify the mixed monomers, and add 0.5 parts by weight of ammonium persulfate.
Add parts by weight to start polymerization and raise the reaction temperature to approximately 70℃.
The emulsion polymerization was carried out for about 2 hours. After the reaction was completed, the mixture was aged at about 80° C. for 1 hour to obtain an aqueous emulsion coating agent for synthetic resin film composites comprising an aqueous copolymer emulsion having a concentration of 40% by weight and a viscosity of 560 cp. Example 2 In a reaction vessel equipped with a stirrer, a reflux condenser, and a thermometer, 150 parts by weight of water, 0.5 parts by weight of sodium acetate, and the following chemical formula as an emulsifier were added: Add 1.5 parts by weight of a copolymerizable emulsifier having an unsaturated double bond and a sulfonic acid group represented by the formula, and then prepare the following composition: 2-ethylhexyl acrylate 53 parts methyl methacrylate 30 parts acrylonitrile 10 parts methacrylic acid 5 Add 100 parts by weight of a mixed monomer containing 2 parts by weight of hydroxyethyl acrylate, stir to emulsify the mixed monomer, and add 0.5 parts by weight of ammonium persulfate.
Add parts by weight to start polymerization and raise the reaction temperature to approximately 70℃.
The emulsion polymerization was carried out for about 2 hours. After completion of the reaction, the mixture was aged at about 80° C. for 1 hour to obtain an aqueous emulsion coating agent for synthetic resin film composites comprising an aqueous copolymer emulsion having a concentration of 40% by weight and a viscosity of 150 cP. Example 3 In a reaction vessel equipped with a stirrer, a reflux condenser, and a thermometer, 150 parts by weight of water, 0.5 parts by weight of sodium acetate, and the following chemical formula as an emulsifier were added: 1.5 parts by weight of a copolymerizable emulsifier having a methallyl group and a sulfonic acid group represented by the following formula were added: 60 parts by weight of ethyl acrylate 34 parts by weight of methyl methacrylate 3 parts by weight of acrylic acid 2.5 parts by weight of hydroxyethyl acrylate Add 0.5 parts by weight of divinylbenzene and 100 parts by weight of mixed monomers, stir to emulsify the mixed monomers, and add 0.5 parts by weight of ammonium persulfate.
Add parts by weight to start polymerization and raise the reaction temperature to approximately 70℃.
The emulsion polymerization was carried out for about 2 hours. After completion of the reaction, the mixture was aged at about 80° C. for 1 hour to obtain an aqueous emulsion coating agent for synthetic resin film composites consisting of an aqueous copolymer emulsion having a concentration of 40% by weight and a viscosity of 220 cP. Example 4 In a reaction vessel equipped with a stirrer, a reflux condenser, and a thermometer, 150 parts by weight of water, 0.5 parts by weight of sodium acetate, and the following chemical formula as an emulsifier were added: 1.0 parts by weight of a copolymerizable emulsifier having an allyl group and a sulfonic acid group represented by the formula and 0.5 parts by weight of polyoxyethylene alkyl phenol ether were added, and then the following composition was prepared: 50 parts by weight of ethyl acrylate, 20 parts by weight of butyl acrylate, and 20 parts by weight of acetic acid. Add 100 parts by weight of a mixed monomer consisting of 15 parts by weight of vinyl, 4 parts by weight of methacrylic acid, and 1 part by weight of glycidyl methacrylate, stir to emulsify the mixed monomer, and add 0.5 parts by weight of ammonium persulfate.
Add parts by weight to start polymerization and raise the reaction temperature to approximately 70℃.
The emulsion polymerization was carried out for about 2 hours. After the reaction was completed, the mixture was aged at about 80° C. for 1 hour to obtain an aqueous emulsion coating agent for synthetic resin film composites consisting of an aqueous copolymer emulsion having a concentration of 40% by weight and a viscosity of 90 cP. Comparative Example 1 Copolymerizable emulsifier having allyl group and sulfonic acid group used as emulsifier in Example 1
An aqueous copolymer emulsion with a concentration of 40% by weight and a viscosity of 420 cP was prepared in the same manner as in Example 1, except that 1.5 parts by weight of polyoxyethylene alkyl phenol ether, a nonionic surfactant, was used instead of 1.5 parts by weight. I got it. Comparative Example 2 Copolymerizable emulsifier having allyl group and sulfonic acid group used as emulsifier in Example 1
The concentration was adjusted in the same manner as in Example 1, except that 1.5 parts by weight of sodium dodecylbenzenesulfonate, an anionic surfactant, was used instead of 1.5 parts by weight.
A copolymerized aqueous emulsion of 40% by weight and a viscosity of 610 cP was obtained. Test Example 1 Aqueous emulsion coating agent for synthetic resin film composite obtained in Examples 1 to 4 and Comparative Examples 1 to 4
The mechanical stability and mechanical stability upon dilution of the aqueous copolymer emulsion obtained in 2 were tested by the following method. The test results were as shown in Table 1. Mechanical stability test Prepare 2,000 g of samples diluted to 30% and 10% by weight solid content, and apply a shearer for 2 hours while circulating the sample at 500 rpm using a stainless steel rotary gear pump. The amount of the solidified material and the coarse particles obtained by passing through a 200-mesh wire gauze was measured, and the numerical value was obtained using the following formula. Numerical value (%) = Amount of gummy coagulation + Amount of coarse particles produced / 2000×
Solid content concentration x 100 The larger the number, the worse the mechanical stability.

[Table] Test Example 2 Aqueous emulsion coating agent for synthetic resin film composite obtained in Examples 1 to 4 and Comparative Examples 1 to 4
Using the aqueous copolymer emulsion obtained in 2 as an anchor coating agent, a gas barrier coating film was prepared under the following conditions. Γ Film used Surface treated polypropylene film Polyester film Γ Anchor coating agent Application amount (solid content) 0.5 g/m ² Drying conditions 120℃, 30 seconds Γ Gas barrier coating agent (vinylidene chloride latex with solid content of 50%) Application Amount (solid content): 5 g/m ² Drying conditions: 120° C., 30 seconds The obtained gas barrier coating film was tested for adhesion, water resistance, and water resistant adhesion. The test results were as shown in Table 2. Γ Adhesion: Cellophane adhesive tape was pressure-bonded to the gas-barrier coating surface, rapidly peeled off, and the coated surface was observed. 〇...The coated surface does not peel off. ×...The coated surface peels off.ΓWater resistance/Water resistant adhesion The gas barrier coating film is immersed in water for 48 hours and the condition is observed. 〇...Remains transparent and does not become cloudy ×...As soon as it becomes cloudy, remove the water on the surface and measure in the same manner as the above adhesion.

[Table] Test Example 3 10 parts by weight of an ultraviolet absorber made of a benzophenone derivative was added to 100 parts by weight of the aqueous emulsion coating agent for synthetic resin film composites obtained in Examples 1 and 3, and the mixture was uniformly stirred and coated. I got the liquid. A coating liquid was applied to a surface-treated polyethylene film using a roll coater so that the solid content was 10 g/m ² and dried with hot air to prepare a film coated with an ultraviolet blocking layer. The ultraviolet blocking layer had excellent adhesion to the polyethylene film and also had excellent water resistance. Test Example 4 Using the aqueous coating agents for synthetic resin film composites obtained in Examples 2 and 4 and the copolymer aqueous emulsions obtained in Comparative Examples 1 and 2 as adhesives for lamination, two types of films were laminated under the following conditions. was laminated. Γ Film used: Surface-treated polypropylene film Polyester film Γ Lamination conditions After applying adhesive at a solid content of 2.5 g/m ² to one side of the surface-treated polypropylene film, dry it, add a polyester film on top, and heat at 110°C.
Pressed for seconds. A 180° peel test was conducted on the obtained laminate film. The test results were as shown in Table 3.

[Table] Test Example 5 Titanyl sulfate was added to the aqueous emulsion coating agent for synthetic resin film composite obtained in Example 2.
A surface-treated polypropylene film and a polyester film were laminated under the same conditions as in Test Example 4 using a coating agent added in weight percent and a coating agent not added to obtain test pieces A and B. This was immersed in water for 48 hours, the moisture on the surface was immediately removed, and a 180° peel test was performed. The test results are shown in Table 4.

[Table] Note that the titanyl sulfate-added coating agent used in Test Example 5 corresponds to the coating agent in claim 2.

Claims (1)

[Claims] 1. Ethylenically unsaturated monomer 80 having no functional group
99.9% by weight and 0.1 to 20% by weight of an ethylenically unsaturated monomer having a functional group. or 1 selected from methallyl group-containing sulfonate copolymerizable emulsifiers.
Or an aqueous emulsion coating agent for synthetic resin film composites, the main component of which is an aqueous copolymer emulsion obtained by emulsion polymerization in an aqueous medium together with 0.1 to 10 parts by weight of two or more copolymerizable emulsifiers. 2 Ethylenically unsaturated monomer 8 having no functional group
99.9% by weight and 0.1 to 20% by weight of an ethylenically unsaturated monomer having a functional group. or 1 selected from methallyl group-containing sulfonate copolymerizable emulsifiers.
Alternatively, an aqueous emulsion coating agent for synthetic resin film composites is prepared by adding an adhesion promoting catalyst to an aqueous copolymer emulsion obtained by emulsion polymerization in an aqueous medium together with 0.1 to 10 parts by weight of two or more copolymerizable emulsifiers.