JPH0768501B2 - Contact adhesive composition for composites - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial field of application> The present invention is a composite of a porous base material such as wood plywood and inorganic board, and a polyolefin foam and sheet, a rubber foam and sheet, and other soundproofing, sound absorbing and heat insulating materials. That is, it relates to an adhesive composition used for producing a composite material.

<Prior Art> Composite materials such as soundproofing and heat insulating materials are usually manufactured by the following method. That is, the adhesive is uniformly applied to a substrate such as plywood by a coating machine such as a roll spreader, and a base material such as a soundproofing material is attached while the adhesive is in a wet state, and a static load is applied at room temperature for adhesion. As the adhesive used in the production of the composite material, a chloroprene rubber-based adhesive in a solvent system and an ethylene-based emulsion in a water-based emulsion type adhesive.
Adhesives such as a vinyl acetate copolymer emulsion or a styrene-butadiene diene latex may be mentioned.

<Problems to be Solved by the Present Invention> Solvent-based adhesives have been shifting to water-based adhesives in recent years due to safety and health problems due to volatilization of organic solvents and dangers such as fire. On the other hand, for water-based emulsion type adhesives, there are developments of two-component type adhesives that use a cross-linking agent in combination, and self-crosslinking type adhesives, but the former has problems of management of pot life, curing time, and compounding amount. However, the latter also has problems of curing temperature and PH, and the adhesive performance of heat resistant adhesive strength and hot water resistant adhesive strength has not been satisfied. To apply the adhesive evenly to a substrate such as plywood with a coating machine such as a roll spreader, and to bond a base material such as a soundproofing agent while the adhesive is in a wet state, and apply a static load at room temperature to adhere. In addition, the drying of the adhesive is slowed down, the initial adhesive strength is delayed, and the workability is poor.

Further, there are various base materials such as soundproofing and heat insulating materials such as foamed polyethylene, felt-impregnated polyethylene sheet, polyethylene air cap sheet, rubber foam, etc., and an adhesive showing excellent adhesiveness especially to inexpensive polyolefin base materials. Is required.

<Means for Solving the Problem> As a result of intensive studies to eliminate the above-mentioned various drawbacks, the present inventors have found that a (meth) acrylic acid ester copolymer latex containing a rosin or a polymerized rosin and an oxazoline group-containing latex are used. By combining a specific amount, we found an adhesive with excellent heat resistance and hot water resistance for the production of composite materials that can bond from wet to dry states.
The present invention has been completed.

That is, the present invention includes [A] a rosin having an acid value of 50 to 150 or 5 to 40% by weight of a polymerized rosin (calculated as a nonvolatile content) and [B] a general formula (1). (In the formula, R ₁ , R ₂ , R ₃ and R ₄ are each independently hydrogen, halogen, alkyl, aralkyl, phenyl or a substituted phenyl group, and R ₅ is an acyclic organic group having an addition polymerizable unsaturated group. The addition-polymerizable oxazoline (a) represented by
(Hereinafter referred to as monomer (a)) and at least one other monomer (b) (hereinafter referred to as monomer (b))
A copolymer latex obtained by emulsion polymerization of [C], a functional group-containing monomer (c) (hereinafter referred to as a monomer (c)) that reacts with [C] oxazoline group, and an acrylic ester or a methacrylic ester (alkyl group). A copolymer latex obtained by emulsion-polymerizing the carbon number of 1 to 12) and optionally other copolymerizable monomer (d) (hereinafter referred to as monomer (d)), Latex [B] and copolymer latex [C]
Of the total amount of 60 to 95% by weight (non-volatile content) and copolymer latex [B] / copolymer latex [C]
The weight ratio of 1/2 to 1/25 (converted to non-volatile content, however, [A],
The present invention relates to a contact adhesive composition for composites, in which the total of [B] and [C] is 100% by weight. .

The rosin or polymerized rosin [A] in the present invention has an acid value of 50 to 150 and improves adhesion to polyolefins, and is not particularly limited as long as it is generally used as a tackifier. A higher softening temperature is more advantageous for heat resistance. Most rosin-based resins are used in the form of esters of glycerin and pentaerythritol, because rosin or polymerized rosin is generally unstable to alkali and poor in aging property. However, in the present invention, the carboxyl group of the rosin-based resin is cross-linked with the oxazoline group to be stable against alkali. Further, generally, when a tackifier is mixed with an acrylic resin, the heat resistance is lowered, but in the present invention, the heat resistance is prevented from being lowered by a cross-linking reaction between the carboxyl group and the oxazoline group of the rosin resin. When the rosin or the polymerized rosin [A] is mixed with the copolymer latex [B] and the copolymer latex [C] to form an aqueous dispersion, the rosin or the polymerized rosin [A] can be used as it is, In consideration of stability during mixing, a high-concentration solution of a water-insoluble organic solvent such as toluene, xylene, or cyclohexane may be used, or an emulsifier may be used as an aqueous emulsion if necessary.

When the acid value of the rosin or the polymerized rosin [A] is less than 50, the reaction of the oxazoline group with the carboxyl group of the rosin or the polymerized rosin is not sufficient and heat resistance and alkali resistance are deteriorated.

On the other hand, when the acid value is more than 150, the reaction with the oxazoline group increases, and it is necessary to reduce the amount of rosin or polymerized rosin [A] to give other desired properties as an adhesive. As a result, the adhesiveness with the polyolefin decreases. Rosin or polymerized rosin [A] is a copolymer latex [B] and a copolymer latex [C].
It is used in an amount of 5 to 40% by weight (non-volatile content conversion) in the non-volatile content of the water dispersion consisting of. When the amount of rosin or polymerized rosin [A] used is less than 5% by weight, no sufficient improvement in adhesive strength with the polyolefin substrate is observed, and conversely, when the amount exceeds 40% by weight, heat resistance is increased. Of the adhesive or the tack of the adhesive after drying is reduced, and the adhesiveness in the dry state is reduced.

The monomer (a) used in the production of the copolymer latex [B] is represented by the general formula (1) (In the formula, R ₁ , R ₂ , R ₃ and R ₄ are each independently hydrogen, halogen, alkyl, aralkyl, phenyl or a substituted phenyl group, and R ₅ is an acyclic organic group having an addition polymerizable unsaturated group. ). As a specific example,
2-vinyl-2-oxazoline, 2-vinyl-4-methyl-2-oxazoline, 2-vinyl-5-methyl-2-
Oxazoline, 2-isopropenyl-2-oxazoline, 2-isopropenyl-4-methyl-2-oxazoline, 2-isopropenyl-5-ethyl-2-oxazoline and the like can be mentioned, and 1 selected from the group One kind or a mixture of two or more kinds can be used. Among them, 2-isopropenyl-2-oxazoline is industrially easily available and suitable.

The monomer (b) used for producing the copolymer latex [B] is not limited as long as it is a monomer copolymerizable with the monomer (a), and examples thereof include methyl (meth) acrylate and (meth) acrylic acid. (Meth) acrylic acid esters such as butyl and 2-ethylhexyl (meth) acrylate; unsaturated nitriles such as (meth) acrylonitrile;
Vinyl esters such as vinyl acetate and vinyl propionate; vinyl ethers such as methyl vinyl ether and ethyl vinyl ether; α-olefins such as ethylene and propylene; halogen-containing α, β-non-containing compounds such as vinyl chloride, vinylidene chloride and vinyl fluoride. Saturated monomers; styrene,
Examples include α, β-unsaturated aromatic monomers such as α-methylstyrene, and one or a mixture of two or more of these can be used.

The monomer (a) and at least one other monomer (b) can be polymerized by a conventionally known emulsion polymerization method. For example, it can be synthesized by a method in which a polymerization catalyst, water, a surfactant and a polymerizable monomer are mixed and polymerized, or a method such as a so-called monomer dropping method, multi-stage polymerization method, pre-emulsion dropping method or the like.

As the polymerization catalyst, any conventionally known one can be used. Examples thereof include ordinary radical polymerization initiators such as hydrogen peroxide, potassium persulfate, and 2,2′-azobis (2-amidinopropane) dihydrochloride. You can

Examples of the surfactant include usual anionic, nonionic, cationic and amphoteric surfactants and reactive surfactants. The polymerization temperature is 0 to 100 ° C, preferably 50 to 80 ° C, and the polymerization time is 1 to 10 hours. Since the oxazoline group of the oxazoline monomer is hydrolyzed with high PH or low PH or reacts with other kinds of monomers, the polymerization is desirably carried out in the range of 3 to 11, preferably 7 to 10.

The monomer (c) used for producing the copolymer latex [C] is not limited as long as it has a functional group containing an active hydrogen atom, and examples thereof include acrylic acid, methacrylic acid, itaconic acid, maleic acid and the like. Saturated carboxylic acids,
Phenols such as o- and m-vinylphenol, alcohols such as hydroxyethyl acrylate, hydroxypropyl methacrylate, N-hydroxymethyl-N-methylacrylamide, amides such as (meth) acrylamide and vinylacetamide, 2-amino Examples thereof include amines such as ethyl (meth) acrylate.

The acrylic acid ester or methacrylic acid ester copolymerized with the monomer (c) used for producing the copolymer latex (c) is not particularly limited, and examples thereof include methyl (meth) acrylate and ethyl (meth) acrylate. ,
Examples thereof include butyl (meth) acrylate and 2-ethylhexyl (meth) acrylate.

The monomer (d) used for producing the copolymer latex [C] is not particularly limited, and examples thereof include unsaturated nitriles such as (meth) acrylonitrile; vinyl esters such as vinyl acetate and vinyl propionate; methyl vinyl ether; Vinyl ethers such as ethyl vinyl ether;
Α-olefins such as ethylene and propylene; halogen-containing α such as vinyl chloride, vinylidene chloride and vinyl fluoride
β-unsaturated monomers; α, β-unsaturated aromatic monomers such as styrene and α-methylstyrene, and the like, and one or a mixture of two or more thereof can be used.

Copolymer latex [B] and copolymer latex [C]
The mixing ratio of 1/2 to 1/25 (calculated as nonvolatile content) is desirable. When the mixing ratio is less than 1/25, it is necessary to increase the copolymerization ratio of the monomer (a) in the copolymer latex [B] in order to sufficiently carry out the crosslinking reaction. However, if the copolymerization ratio of the monomer (a) is too high (20% by weight or more), it is difficult to obtain a stable copolymer latex [B] due to the strong hydrophilicity of the oxazoline group. Further, if the mixing ratio is larger than 1/2, the physical properties of the copolymer latex [C], which contributes to the desired properties as an adhesive as an adhesive, are difficult to be exhibited. Further, if the amount of the monomer (a) in the copolymer latex [B] is less than 0.05 equivalent to the amount of the monomer (c), the crosslinking reaction is not sufficient, and even if it is used in excess of 20 equivalents, more crosslinking occurs. No reaction is desired. In addition, it is economically disadvantageous.

<Advantages of the Invention> When the adhesive composition of the present invention is used for adhesion, it has a volatile component content even though performance such as heat resistance and hot water resistance is equal to or higher than that of a conventional solvent-based adhesive. Since most of it is water, it has the characteristics that there are few problems such as fire risk, working environment, and adverse effects on human body. In addition, since it is an industrial application field in which there is a time lag of several days to one week or more after the adhesion with the base material until the adhesive performance is required, the oxazoline group and the functional group reactive with the oxazoline group are present. No special curing equipment is required because the cross-linking reaction with and proceeds at room temperature. Further, if necessary, a drying facility for far infrared rays or the like is provided on the adhesive coating line, and the workability can be improved by bonding the adhesive to the adherend in a dry state.

Further, the cohesive force of the adhesive is improved by the cross-linking reaction between the oxazoline group and the carboxyl group of the rosin or the polymerized rosin [A] and the functional group that reacts with the oxazoline group in the copolymer latex [C]. It is possible to obtain high hot water adhesive strength.

<Example> Next, the present invention will be specifically described with reference to production examples, examples and comparative examples, but the present invention is not limited to the following examples.

In the following, parts and% are parts by weight and% by weight, respectively, unless otherwise specified.

Production of Oxazoline Group-Containing Copolymer Latex Reference Example 1 A flask equipped with a stirrer, a reflux condenser, a nitrogen introduction tube, a thermometer, and a dropping funnel was charged with 782.4 parts of deionized water and Hitenol N-08 (15% aqueous solution, (Manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd.), put 128 parts, and adjust to pH 9-9.5 with an appropriate amount of ammonia water (28%),
The mixture was heated to 70 ° C while slowly flowing nitrogen gas. 64 parts of a 5% aqueous solution of potassium persulfate was injected therein, and then a previously prepared monomer mixture of 576 parts of butyl acrylate and 64 parts of 2-isopropenyl-2-oxazoline was added dropwise over 3 hours. Nitrogen gas was continuously blown in during the reaction to keep the internal temperature at 70 ° C ± 1 ° C. After the dropping was completed, the same internal temperature was maintained for 2 hours, then the internal temperature was raised to 80 ° C., and stirring was continued for 1 hour to complete the reaction. After that, cool it to a nonvolatile content of 3
9.8% copolymer latex [B-1] was obtained.

Reference Example 2 A copolymer latex [B-2] was obtained by repeating the same operation as in Reference Example 1, except that the composition of the monomer mixture was changed as shown in Table 1 in Reference Example 1.

Production of Copolymer Latex Containing Functional Group Reacting with Oxazoline Group Reference Example 3 157 parts of deionized water was added to one flask equipped with a stirrer, a reflux condenser, a nitrogen introducing tube, a thermometer, and a dropping funnel to adjust the internal temperature. Keep at 75 ° C. After replacing the inside of the reactor with nitrogen, 5 parts of acrylic acid, 420 parts of butyl acrylate, 75 parts of styrene and 190 parts of water, which had been adjusted in advance, Hitenol 18E (20% aqueous solution, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) 50 Of the monomer pre-emulsion consisting of 10 parts, an amount corresponding to 1.5% and potassium persulfate 0.2
The reaction was initiated by adding 5.25 parts of an aqueous solution containing 5 parts and 5 parts of an aqueous solution containing 0.125 parts of sodium hydrogen sulfite. Next, 51 parts of an aqueous solution in which the remaining monomer pre-emulsion and 2.25 parts of potassium persulfate were dissolved and 50 parts of an aqueous solution in which 1.125 parts of sodium bisulfite were dissolved were added dropwise over 3 hours. During the reaction, nitrogen gas was continuously blown in to maintain the internal temperature at 75 ° C ± 1 ° C. Furthermore, after reacting at 80 ° C for 1 hour, it was cooled to 60 ° C and used as a booster to obtain potassium persulfate of 0.
An aqueous solution of 25 parts dissolved in 5.25 parts, sodium bisulfite 0.
5 parts of an aqueous solution in which 125 parts were dissolved was added and held for 1 hour.
Then, the mixture was cooled and adjusted to pH 7.5 to 8.0 with ammonia (28%) to obtain a copolymer latex [C-1]. The nonvolatile content of this copolymer latex [C-1] was 52.0%.

Reference Example 4 A copolymer latex [C-2] was prepared by repeating the same procedure as in Reference Example 3, except that the composition of the polymerizable cavity mixture was as shown in Table 2. Obtained.

All parts shown below are parts by weight in terms of nonvolatile content.

Example 1 20 parts of the polymerized rosin [A-1], 10 parts of the copolymer latex [B-1] obtained in Reference Example 1 and 70 parts of the copolymer latex [C-1] obtained in Reference Example 3 were used at room temperature. Then, the mixture was sufficiently mixed with stirring to obtain an adhesive composition [D-1].

Examples 2 to 4 In Example 1, polymerized rosins [A-1] and [A-2].
And the copolymer latex [B-1] obtained in Reference Examples 1 and 2,
The blending ratios of [B-2] and the copolymer latices [C-1] and [C-2] obtained in Reference Examples 3 and 4 were changed as shown in Table 3 to give Example 1 and Example 1. The same operation was performed to obtain adhesive compositions [D-2] to [D-4].

Comparative Example 1 In Example 1, 20 parts of polymerized rosin ester [F-1] instead of polymerized rosin [A-1] and 10 parts of copolymer latex [B-1] obtained in Reference Example 3 and Reference Example 3 were used. 70 parts of the copolymer latex [C-1] obtained in the above were subjected to the same operations as in Example 1 to obtain a comparative composition [E-1].

Comparative Example 2 20 parts of the copolymer latex [B-1] obtained in Reference Example 1 and 80 parts of the copolymer latex [C-1] were sufficiently stirred and mixed at room temperature to obtain a comparative composition containing no tackifier. Object [E-2]
Got

Comparative Example 3 30 parts of the polymerized rosin [A-1] and 70 parts of the copolymer latex [C-1] obtained in Reference Example 3 were sufficiently stirred and mixed at room temperature to obtain a comparative composition containing no oxazoline group-containing latex. [E-3] was obtained.

Example 5 Adhesive compositions [D-1] to [D-4] obtained in Examples 1 to 4 and Comparative Examples 1 to 3 and comparative composition [E-1].
[E] to [E-3] were used to perform an adhesion test by the following method, and the heat resistance and hot water resistance were examined.

Adhesion Test 1 Adhesive compositions [D-1] to [D-4] and comparative compositions [E-1] to [E] using an applicator on veneer plywood (JAS Class 1 accepted product, thickness 5.5 mm). ~ 3] wet 6mil
(Approx. 150 g / m ² ) applied, and the adhesive remains wet in the adherend (10 mm thick, 30 times expanded polyethylene:
Pef: made by Toray) and the open time is 1
Create an adhesive that adheres adherends after the adhesive has dried for a long time, and then use a tabletop press to apply a static load of 2 kg /
Load m ² for about 1 minute. Cured at room temperature for 1 week, 4cm x 4cm
A two-component epoxy adhesive (Araldite Standard: manufactured by Nagase Ciba Co., Ltd.) was attached to the metal attachment of No. 2. Then, under various conditions, a vertical peel test was performed using an Instron universal testing machine. Peeling speed is 200mm / mi
n. The results are shown in Table 4.

Adhesion test 2 Adhesive compositions [D-1] to [D-4] and comparative compositions [E-1] to [E] using an applicator on veneer plywood (JAS Class 1 acceptable product, thickness 5.5 mm). ~ 3] wet 6mil
(Approx. 150 g / m ² ) is applied, and the adhesive is used in the wet state to adhere the adherend (polyethylene sheet, thickness 0.5 mm corona discharge treated: index 38) and open time is 1 hour After the adhesive is in a dry state, an adhesive is adhered to the adherend, and then a static load of 2 kg / m ² is applied for about 1 minute with a tabletop press. After curing for 1 week at room temperature, it was cut into a strip with a width of 2.5 cm and subjected to a 180 degree peeling test under various conditions using an Instron universal tester. The peeling speed was 200 mm / min. The results are shown in Table 5.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Akira Fujiwara, Inventor Akihiro Fujiwara, 992, Nishi-oki, Kokihama, Aboshi-ku, Himeji-shi, Hyogo Prefecture Hiroyuki Taniguchi, Inspector, Himeji Research Institute, Nippon Catalysis Chemical Co., Ltd.

Claims (1)

[Claims] 1. [A] A rosin having an acid value of 50 to 150 or 5 to 40% by weight of a polymerized rosin (calculated as a nonvolatile content), and [B] a general formula (1). (In the formula, R ₁ , R ₂ , R ₃ and R ₄ are each independently hydrogen, halogen, alkyl, aralkyl, phenyl or a substituted phenyl group, and R ₅ is an acyclic organic group having an addition polymerizable unsaturated group. The addition-polymerizable oxazoline (a) represented by
And an oxazoline group-containing copolymer latex obtained by emulsion-polymerizing at least one other monomer (b), and [C] a functional group-containing monomer (c) that reacts with an oxazoline group and an acrylic acid ester or a methacrylic acid ester. (A carbon number of the alkyl group is 1 to 12) and, if necessary, a copolymer latex obtained by emulsion-polymerizing another copolymerizable monomer (d), which is copolymerized with the copolymer latex [B]. Combined latex [C]
Is 60 to 95% by weight (calculated as nonvolatile content), and the addition-polymerizable oxazoline (a) in the copolymer latex [B] is less than 20% by weight, and the amount of addition-polymerizable oxazoline (a) is Is 0.05 to 20 equivalents relative to the functional group-containing monomer (c), and copolymer latex [B] / copolymer latex [C]
The weight ratio of 1/2 to 1/25 (converted to non-volatile content, however, [A],
The contact adhesive composition for composites, wherein the total of [B] and [C] is 100% by weight.