JPH02155977A - Contact adhesive composition for composite material - Google Patents

Abstract

PURPOSE:To prepare an adhesive excellent in the heat and hot water resistance of adhesion and suitable for the use in producing a composite material by compounding rosin and two specific copolymer latices. CONSTITUTION:This composition comprises (A) 5-40wt.% (in terms of nonvolatile content) rosin or polymerized rosin with an acid value of 50-150; (B) an oxazoline copolymer latex obtd. by emulsion polymerization of an addition- polymerizable oxazoline of formula 1 [wherein R1, R2, R3, and R4 are each H, halogen, alkyl, aralkyl, or (substd.)phenyl; and R5 is an acyclic org. group contg. an addition-polymerizable unsatd. group] with at least one other monomer; and (C) a copolymer latex obtd. by emulsion polymerization of an oxazoline-reactive functional monomer with a (meth)acrylate ester(1-12C alkyl) and, if necessary, other copolymerizable monomer. The sum of components B and C is 60-95wt.%, the sum of components A, B and C is 100wt.%, and the wt. ratio of B to C is (1:2)-(1:25) (in terms of nonvolatile content).

Description

[Detailed Description of the Invention] <Industrial Application Field> The present invention is a composite of porous substrates such as wood plywood and inorganic boards, and soundproofing, sound absorbing, and heat insulating materials such as polyolefin foams and sheets, rubber foams and sheets, etc. , that is, adhesive compositions used in the production of composite materials.

<Prior Art> Composite materials such as soundproofing and heat insulating materials are usually manufactured by the following method. That is, adhesive is uniformly applied to a substrate such as plywood using a coating machine such as a roll spreader, a base material such as a soundproofing material is attached while the adhesive is still wet, and a static load is applied to adhere the adhesive at room temperature. . Adhesives used in the manufacture of composite materials include chloroprene rubber-based solvent-based adhesives and ethylene-based emulsion-based water-based adhesives.
Examples include adhesives such as vinyl acetate copolymer emulsion or styrene-butadiene copolymer latex.

Problems to be Solved by the Present Invention In recent years, solvent-based adhesives are being replaced by water-based adhesives due to safety and health problems caused by volatilization of organic solvents and dangers such as fire.

On the other hand, water-based emulsion adhesives have been developed into two-component types that use a crosslinking agent, as well as self-crosslinking types, but the former have problems with pot life, curing time, and control of compounding amount. Regarding the latter, there are also problems with the effects of curing temperature and pH, and the adhesive performance of heat-resistant adhesive strength and hot water-resistant adhesive strength is not yet satisfactory. The adhesive is applied uniformly to the substrate, and a base material such as a soundproofing agent is attached while the adhesive is wet, and a static load is applied at room temperature to bond it, which slows down the drying of the adhesive and slows down the development of initial adhesive strength. , workability is also poor.

Furthermore, there are a variety of base materials for soundproofing and heat insulating materials, such as foamed polyethylene, felt-impregnated polyethylene sheets, polyethylene air cap sheets, and rubber foam, and adhesives that exhibit particularly excellent adhesion to inexpensive polyolefin base materials. is required.

(Means for Solving the Problems) As a result of intensive studies to eliminate the various drawbacks described above, the present inventors have developed a (meth)acrylate copolymer latex containing rosin or polymerized rosin and a latex containing an oxazoline group. By combining specific amounts, we discovered an adhesive with excellent heat-resistant adhesive strength and hot water-resistant adhesive strength for the production of composite materials that can be bonded from wet to dry conditions.
The present invention has now been completed.

That is, the present invention comprises [A] rosin or polymerized rosin having an acid value of 50 to 150 in an amount of 5 to 40% by weight (in terms of non-volatile content) and [B] general formula (1) (in which R+, R2, R3, are each independently hydrogen,
It is a halogen, alkyl, aralkyl, phenyl or substituted phenyl group, and R9 is an acyclic organic group having an addition polymerizable unsaturated group. ) (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 that reacts with an oxazoline group, -(c) (hereinafter referred to as monomer (C)) and an acrylic ester or methacrylic From a copolymer latex obtained by emulsion polymerization of an acid ester (alkyl group has 1 to 12 carbon atoms) and, if necessary, other copolymerizable monomers (d) (hereinafter referred to as monomers (d)). Become.

Copolymer latex [B] and copolymer latex [C]
The total amount of is 60 to 95% by weight (in terms of non-volatile content), and copolymer latex [B]/copolymer latex [C]
The weight ratio of 172 to 25 (in terms of non-volatile matter,
, [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 adhesiveness to polyolefin, and is not particularly limited as long as it is generally used as a tackifier. , a higher softening temperature is advantageous for heat resistance. Rosin or polymerized rosin is generally unstable to alkali and has poor aging properties, so rosin resins are mostly used in the form of esters of glycerin and santaerythol. However, in the present invention, the carboxyl group of the rosin resin is subjected to a crosslinking reaction with the oxazoline group, thereby making it stable against alkalis.

In addition, heat resistance generally decreases when a tackifier is mixed with an acrylic resin, but in the present invention, a decrease in heat resistance is prevented by crosslinking the carboxyl group and oxazoline group of the rosin resin. When mixing rosin or polymerized rosin [A] with copolymer latex [B] and copolymer latex [C] to form an aqueous dispersion.

Rosin or polymerized rosin [A] can be used as is, but in consideration of stability during mixing, it may be made into a highly concentrated solution of a water-insoluble organic solvent such as toluene, xylene, or cyclohexane, or if necessary, an emulsifier may be used to make it aqueous. It may also be used as an emulsion.

If the acid value of the rosin or polymerized rosin [A] is less than 50, the reaction of the oxazoline group with the carboxyl group of the rosin or polymerized rosin will be insufficient, resulting in a decrease in heat resistance and alkalinity.

Furthermore, if the acid value is greater than 150, the reaction with the oxazoline group increases, and in order to provide other desired properties as an adhesive, it is necessary to reduce the amount of rosin or polymerized rosin [A]. As a result, the adhesiveness with polyolefin decreases. Rosin or polymerized rosin [A] is composed of copolymer latex [B] and copolymer latex [C
5 to 40% by weight of the nonvolatile content of the aqueous dispersion consisting of
(converted to non-volatile content). If the amount of rosin or polymerized rosin [A] used is less than 5% by weight, no sufficient improvement in adhesion with the polyolefin base material will be observed.On the contrary, if the amount exceeds 40% by weight, heat resistance The tackiness of the adhesive after it dries is reduced, and the adhesion in the dry state is reduced.

The monomer (a) used for producing the copolymer latex [B] is represented by the general formula (1) (wherein R1, R2,
R3 and & each independently represent hydrogen, halogen, alkyl,
aralkyl, phenyl or substituted phenyl group, R
s is an acyclic organic group having an addition polymerizable unsaturated group. )
A specific example is 2-vinyl-
2-oxacillin, 2-vinyl-4-methyl-2-oxazoline, 2-vinyl-5-methyl-2-oxazoline, 2-impropenyl-2-oxazoline.

2-impropenyl-4-methyl-2-oxacillin,
Examples include 2-impropenyl-5-ethyl-2-oxacillin, and one type or a mixture of two or more types selected from these groups can be used. Among them,
2-impropenyl-2-oxazoline is suitable because it is industrially easily available.

The monomer (b) used in the production of the copolymer latex [B] is not limited as long as it is copolymerizable with the monomer (a). For example, methyl (meth)acrylate, ( (meth)acrylic esters such as butyl meth)acrylate 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- and β-unsaturation such as vinyl chloride, vinylidene chloride, and vinyl fluoride Motsumers; styrene, α-
Examples include α,β-unsaturated aromatic motumers such as methylstyrene, and one or a mixture of two or more of these can be used.

Monomer (a) and at least one other monomer (
b) can be polymerized by a conventionally known emulsion polymerization method. For example, a method in which a polymerization catalyst, water, a surfactant, and a polymerizable monomer are mixed all at once, or a so-called seven-mer dropping method, a multistage polymerization method, etc. It can be synthesized by a method such as a pre-emulsion dropping method.

Any conventionally known polymerization catalyst can be used, including common radical polymerization initiators such as hydrogen peroxide, potassium persulfate, and 2.2°-azobis(2-amidinopropane) dihydrochloride. Can be done.

In addition, the surfactant is a normal 7-ion type.

Nonionic, cationic, amphoteric surfactants, reactive surfactants, etc. can be mentioned. 0 Polymerization temperature is 0-1
00°C, preferably 50-80°C, polymerization time 1-10
It's time. Since the oxazoline group of the oxazoline monomer is hydrolyzed at a high pH of 1 or a low pH or reacts with other types of monomers, it is desirable that the polymerization be carried out at a pH in the range of 3 to 11, preferably 7 to 10.

Monomer (c) used in the production of copolymer latex [C]
) is not limited as long as it has a functional group containing an active hydrogen atom; for example, acrylic acid.

Unsaturated carboxylates such as methacrylic acid, itaconic acid and maleic acid, phenols such as 0- and m-vinylphenol, hydroxyethyl acrylate, hydroxypropyl methacrylate, N-hydroxymethyl-N
-Alcohols such as methylacrylamide, amides such as (meth)acrylamide and vinylacetamide, 2-
Examples include amines such as aminoethyl (meth)acrylate.

Monomer (C) used in the production of copolymer latex (C)
) There are no particular restrictions on the acrylic ester or methacrylic ester to be copolymerized with (meth).
Examples include methyl acrylate, ethyl (meth)acrylate, butyl (meth)acrylate, and 2-ethylhexyl (meth)acrylate.

Monomer (d) used in the production of copolymer latex [C]
) is not particularly limited, and includes, for example, 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- such as ethylene and propylene. Olefins; molded vinyl,
Halogen-containing α, β- such as vinylidene chloride and vinyl fluoride
Unsaturated motsumers; α,β-unsaturated aromatic motsumers such as styrene and α-methylstyrene, and the like, and one type or a mixture of two or more of these can be used.

Copolymer latex CB] and copolymer latex [C]
The mixing ratio is preferably 1/2 to 25 (in terms of non-volatile content).
If the mixing ratio is less than 1/25, it is necessary to increase the copolymerization ratio of monomer (a) in the copolymer latex [Bl] in order to sufficiently carry out the crosslinking reaction. However, seven months (a)
If the copolymerization ratio is too high (20% by weight or more), it will be difficult to obtain a stable copolymer latex [B] due to the strong hydrophilicity of the oxazoline group, and if the mixing ratio is more than 1/2, it will be difficult to obtain a stable copolymer latex [B]. The physical properties of the copolymer latex [C], which contributes to the desired properties as an adhesive, are difficult to exhibit, and the monomer (a) in the copolymer latex [B]
If the amount is less than 0.05 equivalents with respect to Shitsummer (C), the crosslinking reaction will not be sufficient, and even if it exceeds 20 equivalents, further crosslinking reaction is not desired. It is disadvantageous.

<Effects of the Invention> When the adhesive composition of the present invention is used for adhesion, although its properties such as heat resistance and hot water resistance are equivalent to or better than conventional solvent-based adhesives, it does not contain volatile components. Since most of it is water, it is characterized by having fewer problems such as fire hazards in the working environment and adverse effects on the human body. In addition, after adhesion to the base material, it takes several days until the adhesive performance is required, and since the crosslinking reaction between the group and the reactive functional group proceeds at room temperature, no special curing equipment is required. If necessary, drying equipment such as far infrared rays may be installed in the adhesive coating line to allow the f&adhesive to adhere to the adherend in a dry state, thereby improving workability.

Then, the oxazoline group and rosin or polymerized rosin [A
By improving the cohesive strength of the adhesive through a crosslinking reaction between the carboxyl group of I and the functional group that reacts with the oxazoline group in the copolymer latex [C], adhesive strength with high heat resistance and hot water resistance can be obtained. .

<Examples> Next, the present invention will be specifically explained using production examples, working examples, and comparative examples, but the present invention is not limited to the following examples.

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

Reference example of oxazoline latex l In a flask equipped with a stirrer, a reflux condenser, a nitrogen inlet pipe, and a dropping funnel with a thermometer, 782° 4 parts of deionized water, Hitenol N-08 (15% aqueous solution, Daiichi Kogyo Seiyaku Co., Ltd.) (manufactured by) 1
Add 28 parts and adjust the pH to 9 with an appropriate amount of ammonia water (28%).
Adjust to ~9.5 and heat to 70 while slowly flowing nitrogen gas.
Heated to °C.

64 parts of a 5% aqueous solution of potassium persulfate was poured into it, followed by 576 parts of butyl acrylate, which had been prepared in advance.
- A monomer mixture of 64 parts of impropenyl-2-oxazoline was added dropwise over a period of 3 hours.Nitrogen gas was continuously blown during the reaction, and the internal temperature was maintained at 70°C ± 1°C.The internal temperature remained the same for 2 hours after the completion of the dropwise addition. After the temperature was maintained at 80°C, the internal temperature was raised to 80°C, and stirring was continued for 1 hour to complete the reaction. After that, it was cooled and a copolymer latex with a non-volatile content of 39.8% [
B-11 was obtained.

Reference Example 2 Copolymer latex [B-2] was obtained by repeating the same operations as Reference Example 1 except that the composition of the monomer mixture was as shown in Table 1. .

Reference Example 3 Add 157 parts of deionized water to a flask equipped with a stirrer, reflux condenser, nitrogen inlet tube, thermometer, and dropping funnel, and keep the internal temperature at 75°C. After replacing with nitrogen, add 5 parts of acrylic acid and 42 parts of butyl acrylate that had been prepared in advance.
0 parts, 75 parts of styrene, 190 parts of water, and 50 parts of Hytenol 18E (20% aqueous solution, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.), an amount equivalent to 1.5% and potassium persulfate. Aqueous solution in which 0.25 part of 5.
The reaction was started by adding 5 parts of an aqueous solution containing 25 parts of sodium hydrogen sulfite and 0.125 parts of sodium bisulfite.Then, the remaining monomer pre-emulsion and superf! acid potassium 2.25
51 parts of an aqueous solution containing 1.125 parts of sodium bisulfite and 50 parts of an aqueous solution containing 1.125 parts of sodium bisulfite were added dropwise over 3 hours. During the reaction, nitrogen gas was continued to be blown in to maintain the internal temperature at 75°C±1°C. After reacting at 80°C for 1 hour, the mixture was cooled to 60°C, and as a booster, 5.25 parts of an aqueous solution in which 0.25 parts of potassium persulfate was dissolved, and
W1. Aqueous solution in which 125 parts of sodium hydrogen O was dissolved 5
1 part was added and held for 1 hour. Thereafter, the mixture was cooled and adjusted to pH 7.5-8°O with ammonia (28%) to obtain copolymer latex [C-1]. This copolymer latex [
C-13 had a nonvolatile content of 52.0%.

Reference Example 4 In Reference Example 3, the same operation as in Reference Example 3 was repeated except that the composition of the polymerizable monomer mixture was as shown in Table 2 to prepare copolymer latex [C-2]. Obtained.

All parts shown below are parts by weight calculated as non-volatile content.

Example 1 20 parts of polymerized rosin [A-1], 10 parts of copolymer latex [B-1] obtained in Reference Example 1, and 1170 parts of copolymer latex [C-1] obtained in Reference Example 3 were sufficiently mixed at room temperature. The adhesive composition [D-1] was obtained by stirring and mixing.

Examples 2 to 4 In Example 1, polymerized rosin [A-1] [A-2]
and copolymer latex obtained in Reference Example 1.2 [B-1]
, [B-2] and the copolymer latex obtained in Reference Example 3.4 [C-1] and [C-21] by changing the types and proportions as shown in Table 3, and producing the same as Example 1. Similar operations were performed to obtain adhesive compositions [D-2] to [D-4].

Comparative Example 1 In Example 1, 120 parts of polymerized rosin ester [F-1] and 10 parts of the copolymer latex [B-1] obtained in Reference Example 3 were used instead of polymerized rosin [A-11]. 70 parts of copolymer latex [C-1] was subjected to the same operation as in Example 1 to obtain a comparative composition [E-11].

Comparative Example 2 20 parts of the copolymer latex [B-1] obtained in Reference Example 1 and 1180 parts of the copolymer latex [C-1] were sufficiently stirred and mixed at room temperature to prepare a comparative composition containing no tackifier [ E-
I got 23.

Comparative Example 3 A comparative composition containing no oxazoline group-containing latex was prepared by thoroughly stirring and mixing 30 parts of polymerized rosin [A-1] and 70 parts of copolymer latex [C-1] obtained in Reference Example 3 at room temperature. [E-33 was obtained.

Example 5 Adhesive compositions obtained in Examples 1 to 4 and Comparative Examples 1 to 3 [
D-1] to [D-4] and comparative composition [E-1] to
Using [E-3], an adhesion test was conducted in the following manner to examine heat-resistant adhesion and hot water-resistant adhesion.

Adhesive compositions [0-1] to [0-1] were applied using an applicator onto veneer plywood (JAS-type approved product, thickness 5.5 mm).
D-4] and comparative compositions [E-1] to [E-3] were applied to a thickness of Z-/tromil (approximately 150 g/m'), and the adhesive was left in a wet state. One to bond the adherend (10 mm thick, 30 times expanded polyethylene foam) manufactured by Toshisha Co., Ltd. and the other to bond the adherend after allowing an hour of open time so that the adhesive is dry. was created, and then a static load of 2 kg/m'' was applied using a tabletop press to approximately 1
load. After curing at room temperature for one week, a 4 cm x 4 cm metal attachment was attached with a two-component poxy adhesive (Araldite Standard, manufactured by Nagase Ciba Co., Ltd.). Vertical peel tests were then conducted under various conditions using an Instron universal testing machine. Peeling speed is 200mm
/min. The results are shown in Table 4.

11-way Yingmei-” Plywood plywood (JAS-type approved product, thickness 5.5 m + 1
1) Using an applicator, apply adhesive compositions [D-1] to [D-4] and comparative composition [E
-1] to [E-3] wet 6 ml (approximately 150
The adhesive was applied to a thickness of 100 g/g/g), and the adhesive was left wet for 1 hour to adhere to the adherend (polyethylene sheet, 0.5 mm thick, corona discharge treated: index 38). After the adhesive is dry, a material to be bonded to the adherend is prepared, and then a static load of 2 kg/rn' is applied for about 1 minute using a bench press. After curing at room temperature for one week, the strips were cut into 2.5 cm wide strips and subjected to a 180 degree peel test using an Instron universal testing machine under various conditions. The peeling speed was 200 mm/min. The results are shown in Table 5.

Table 1: 100% broken foam, O: 80% or more, 1 broken foam.

Δ: Adhesive cohesive failure, ×: Adhesive valve V polyethylene foam interfacial peeling table 014%; non-volatile content equivalent) A-2SN-Tack 75Q (tt; tt
= 137°C) 140F-I 5N-E
X7108(//; /l = 12
4℃) 14 All non-volatile content is 50%.

Claims (1)

[Claims] 1. [A] rosin or polymerized rosin having an acid value of 50 to 150 in an amount of 5 to 40% by weight (in terms of nonvolatile content); [B] General formula (1) ▲ Numerical formula, chemical formula, table, etc. There is a An oxazoline group-containing copolymer latex obtained by emulsion polymerization of addition-polymerizable oxazoline (a) represented by (a) and at least one other monomer (b), and [C] which reacts with the oxazoline group. A copolymer obtained by emulsion polymerization of a functional group-containing monomer (c), an acrylic ester or a methacrylic ester (alkyl group has 1 to 12 carbon atoms), and if necessary, other copolymerizable monomers (d). Copolymer latex [B] and copolymer latex [C] consisting of polymer latex
The total amount of is 60 to 95% by weight (in terms of non-volatile content), and copolymer latex [B]/copolymer latex [C]
The weight ratio of 1/2 to 25 (in terms of nonvolatile content,
, [B], and [C] totaling 100% by weight).