JPH0369954B2 - - Google Patents

Description

[Detailed description of the invention]

<Industrial Application Field> The present invention relates to an aqueous emulsion type adhesive composition, and more particularly to an adhesive composition having excellent low-temperature adhesive properties. <Prior Art> Conventionally, as a contact adhesive, a solvent-based adhesive in which, for example, chloroprene rubber is dissolved in an organic solvent such as toluene or n-hexane has been widely used. Utilizing its excellent physical properties such as adhesive strength, heat resistance, and water resistance, it is used in various fields such as woodworking, architectural civil engineering, and automobile interiors, which cover various adherends such as metal, rubber, and wood. It's on. The method for using such solvent-based contact adhesives is to apply the adhesive to both sides, allow an open time of 10 to 60 minutes, or longer depending on the conditions, and then adhere using tactile pressure. High adhesive strength can be obtained in 1 day to 1 week. However, these do not have permanent pressure sensitivity, and as the open time increases, the pressure sensitivity decreases and the adhesive strength also decreases. Therefore, bonding is required in an optimal open time, but since this time varies depending on various conditions including temperature, troubles such as poor adhesion are likely to occur. Furthermore, these solvent-based contact adhesives contain large amounts of highly flammable organic solvents, which poses problems such as fire hazards, adverse effects on the working environment, and the human body. On the other hand, water-based emulsion type contact adhesives can solve many of the above-mentioned problems specific to solvent-based contact adhesives, but they inherently have the drawbacks of poor adhesion, heat resistance, and water resistance. and
Various attempts have been made to improve this point. For example, according to Japanese Patent Publication No. 55-18476, mono- or dialkyl ethers of ethylene glycol, propylene glycol, or dimers thereof are blended into an emulsion polymer of a monomer mixture containing a vinyl ester monomer. A water-based contact cement with excellent adhesive properties has been proposed. However, in this method, in order to maintain the stability of the emulsion polymer when blending alkylene glycol etc., it is necessary to blend it in the presence of a lipophilic solvent such as toluene or xylene. cannot be said to have sufficient adhesion, especially at low temperatures. Therefore, the water-based contact adhesives that have been developed so far have insufficient (1) drying properties, (2) adhesive properties, (3) heat resistance, and (4) water resistance, etc. compared to solvent-based ones. The current situation is that the transition to water-based products in the field is not progressing as expected. In addition, there has recently been an increase in the use of heat insulating materials such as polyethylene, polypropylene, and polystyrene for the purpose of energy conservation, and these are used, for example, in insulation construction methods for rooftop waterproofing, and for insulation and soundproofing purposes on walls, floors, etc. . It is desired to develop water-based adhesives with good adhesion properties for these insulation materials, but they have problems such as (1) short open time, (2) slow drying, and (3) low pressure sensitivity at low temperatures. Problems remain. <Problems to be Solved by the Invention> The present inventors have worked diligently to obtain a water-based adhesive that maintains the heat resistance, adhesive strength, and water resistance of conventional solvent-based contact adhesives and also has excellent low-temperature adhesion properties. As a result of this study, we have arrived at the present invention. <Means for solving the problems> That is, the present invention comprises 50 to 100% by weight of an acrylic ester (a) having an alkyl group having 4 to 8 carbon atoms and 0 to 100% by weight of other polymerizable monomers (b). A polymer emulsion (A) obtained by emulsion polymerization of a monomer component consisting of 50% by weight, 60 to 95% by weight (in terms of non-volatile content), and
Coumaron resin, phenolic resin, terpene resin,
Tackifier (B) consisting of one or more selected from terpene-phenol resin, petroleum resin, rosin resin, and their derivatives (B) 5 to 40% by weight (in terms of non-volatile content) (However, the non-volatile content of (A) The total non-volatile content of (B) is 100% by weight.)
The solubility in 100 parts by weight and 100 g of water is 50 at 20°C.
The present invention relates to an adhesive composition comprising 1 to 15 parts by weight of an alkylene glycol derivative (C) of 1 to 15 g or less. Examples of the acrylic ester (a) having an alkyl group having 4 to 8 carbon atoms (hereinafter referred to as acrylic ester (a)) used in the present invention include n-butyl acrylate, isobutyl acrylate, hexyl acrylate, 2- Examples include ethylhexyl acrylate, and one or two of these
More than one species can be used. Acrylic ester (a) is used to develop initial adhesive properties in the adhesive composition of the present invention, and contains 50 to 50% of the monomer components.
Use within 100% by weight. If the ratio of acrylic ester (a) is less than 50%, the polymer will become hard and
Initial adhesion is reduced. Other polymerizable monomers (b) used in the present invention are not particularly limited as long as they can be copolymerized with the acrylic ester (a), such as acrylonitrile, styrene, cyclohexyl acrylate, hydroxyethyl acrylate, Hydroxypropyl acrylate, glycidyl methacrylate, allyl glycidyl ether, N-methylol acrylamide, acrylamide, acrylic acid, methacrylic acid, itaconic acid,
Examples include maleic acid and half esters thereof, and one or more of these can be used. In the present invention, the other polymerizable monomer (b) is used in an amount of 0 to 50% by weight based on the polymerizable monomer component, if necessary. If the amount exceeds 50% by weight, the amount of the acrylic acid ester (a) used will be less than 50% by weight, and the initial adhesiveness will deteriorate. In addition, when using other polymerizable monomers (b), acrylic acid, methacrylic acid, itaconic acid, etc. are used in an amount of 5% by weight or less, more preferably 3% by weight or less in the polymerizable monomer component. It is preferable to use a carboxyl group-containing polymerizable monomer because it may improve the adhesive strength of the adhesive composition. The polymer emulsion (A) in the present invention is produced by emulsion polymerization of monomer components consisting of the acrylic ester (a) and other polymerizable monomers (b) used as necessary. For emulsion polymerization, any conventionally known emulsion polymerization method can be employed. For example, the monomer components are emulsified in an aqueous medium with a polymerization initiator under an inert gas atmosphere, using a known emulsifier if necessary. All it has to do is polymerize. At this time, the emulsifier that can be used if necessary is not particularly limited, and includes, for example, anionic emulsifiers such as sodium lauryl sulfate and sodium dodecylbenzenesulfonate, and nonionic emulsifiers such as polyethylene glycol nonyl phenyl ether. Examples include emulsifiers and cationic emulsifiers typified by dodecyltrimethylammonium chloride. Examples of polymerization initiators that can be used include ammonium persulfate, potassium persulfate, hydrogen peroxide, butyl hydroperoxide, and 2,2'-azobis(2-amidinopropane).
Dihydrochloride and the like can be mentioned. Furthermore, during emulsion polymerization, the molecular weight may be adjusted appropriately using a known molecular weight regulator. The polymer emulsion (A) thus obtained can be fully used as it is in the adhesive composition of the present invention, but it may be used after adjusting the pH if necessary. Examples of the tackifier (B) used in the present invention include coumaron resin, phenol resin, terpene resin, terpene-phenol resin, petroleum resin, rosin resin, and derivatives thereof. When mixing these tackifiers (B) and the polymer emulsion (A) to form an aqueous dispersion, the tackifier (B) can be used as is, but the stability at the time of mixing must be taken into consideration. It may be used as a highly concentrated solution of a water-insoluble organic solvent such as toluene, xylene, or cyclohexane, or as an aqueous emulsion using an emulsifier if necessary. The tackifier (B) is used in an amount of 5% to 40% by weight (in terms of nonvolatile content) in the nonvolatile content of the aqueous dispersion consisting of the tackifier (B) and the polymer emulsion (A). do. If the amount of tackifier (B) used is less than 5% by weight, the initial adhesiveness will be low and sufficient adhesive strength will not be obtained.On the other hand, if the amount used is more than 40% by weight, the adhesive composition will is undesirable because it becomes hard, making it difficult to obtain room-temperature adhesion and also reducing heat resistance. Alkylene glycol derivatives used in the present invention
(C) has a solubility of 50 g or less in 100 g of water at 20°C. If an alkylene glycol derivative with a solubility in 100 g of water exceeds 50 g is used, the stability of the polymer emulsion (A) may decrease during compounding, resulting in the formation of lumps, or the drying of the adhesive composition may be significantly delayed. Particularly, work efficiency at low temperatures is extremely reduced. Furthermore, the adhesive strength is insufficient when used at low temperatures. The solubility of alkylene glycol derivatives in water at 20°C is determined by Solvent Pocket Book (edited by the Organic Synthetic Chemistry Association, published by Ohmsha)
This can be easily determined by, etc. Examples of alkylene glycol derivatives (C) having a solubility in 100 g of water at 20°C of 50 g or less include ethylene glycol diethyl ether, ethylene glycol dibutyl ether, propylene glycol monobutyl ether, ethylene glycol monoethyl ether acetate, ethylene glycol monobutyl ether acetate, and diethylene glycol Monobutyl ether acetate, 1-ethoxy 2-propanol acetate, etc.
One or more of these can be used. In the present invention, it is preferable to use alkylene glycol alkyl acetate in order to obtain particularly excellent low-temperature adhesion. These alkylene glycol derivatives (C) are used in an amount of 1 to 15 parts by weight based on 100 parts by weight of the aqueous dispersion consisting of the polymer emulsion (A) and the tackifier (B). If the amount of alkylene glycol derivative (C) used is less than 1 part by weight, sufficient low-temperature adhesion cannot be obtained, and conversely, if the amount is more than 15 parts by weight, drying of the adhesive composition is slow. This is not preferable because it also reduces heat resistance. The adhesive composition of the present invention is a polymerizable emulsion (A)
and an aqueous dispersion consisting of a tackifier (B) and 100
g of an alkylene glycol derivative (C) having a solubility in water of 50 g or less at 20°C. When blending the alkylene glycol derivative (C) into the aqueous dispersion, there are no particular restrictions on the timing or method; for example, it may be added during the production of the polymerizable emulsion (A), or the organic It may be used as part of a medium when obtaining a solvent solution or an aqueous emulsion, or it may be added to an aqueous dispersion. The adhesive composition of the present invention may further contain well-known additives, such as the above-mentioned additives, without departing from the object of the present invention.
Organic solvents other than the alkylene glycol derivative (C) having a solubility in water of 50 g or less at 20° C., a wetting agent, an antifoaming agent, a penetrating agent, a leveling agent, etc. may be blended as appropriate. <Effects of the invention> When the adhesive composition of the invention is used for adhesion,
Although the properties such as heat resistance and water resistance are equivalent to or better than conventional solvent-based adhesives, the majority of the volatile component is water, so there is a risk of fire and
It is characterized by having fewer problems such as adverse effects on the working environment and the human body. Furthermore, since the optimum open time varies little due to various conditions including temperature, troubles such as poor adhesion are less likely to occur. Furthermore,
Since it has excellent pressure sensitivity not only at high temperatures but also at low temperatures, high adhesive strength can be obtained even when applied at low temperatures. <Examples> The present invention will be explained in detail below using examples. Note that the scope of the present invention is not limited in any way by this example. All parts in the examples are by weight. Example 1 200 parts of water is added to a reaction vessel equipped with a stirrer, a thermometer, and a cooling tube, and the internal temperature is maintained at 75°C. After replacing the inside of the reaction vessel with nitrogen, add 501 parts of butyl acrylate, 90 parts of styrene, 6 parts of N-methylolacrylamide, 3 parts of acrylic acid, and water, which had been prepared in advance.
The reaction was started by adding 6 g of an aqueous solution containing 0.3 parts of ammonium persulfate and 5% by weight of a monomer pre-emulsion consisting of 150 parts and 12 parts of Levenol WZ (manufactured by Kao Corporation). did. Then,
remaining monomer pre-emulsion and 2.7 g
54 g of an aqueous solution in which ASP was dissolved was uniformly dropped over 3 hours. After further reacting at 80°C for 1 hour, the mixture was cooled and neutralized with ammonia to obtain a milky white polymerizable emulsion (1) with a pH of 8.0. This polymerizable emulsion (1) had a solid content of 59.8% and a viscosity of 4000 cps. Per 100 parts of polymerizable emulsion (1), 30 parts of terpene phenol resin emulsion (softening temperature 130°C, non-volatile content 45%) and rosin derivative resin emulsion (softening temperature 100°C, non-volatile content 50%) are used as tackifiers. Adhesive composition (1) was prepared by mixing 30 parts of ethylene glycol monobutyl ether acetate and 8 parts of ethylene glycol monobutyl ether acetate at room temperature for 1 hour.
I got it. There was almost no formation of aggregates due to the addition of ethylene glycol monobutyl ether acetate. Examples 2-3 Adhesion was carried out in the same manner as in Example 1, except that 8 parts each of ethylene glycol monoethyl ether acetate (Example 2) and ethylene glycol dibutyl ether (Example 3) were used in place of ethylene glycol monobutyl ether acetate. Agent composition (2) ~
I got (3). Ethylene glycol monoethyl ether acetate and ethylene glycol dibutyl ether each have a solubility of 22.9 in 100 g of water at 20°C.
g, 0.2 g, and the amount of aggregates generated when the polymerizable emulsion (1) was blended with these alkylene glycol derivatives (C) was examined by passing the above adhesive composition through a 100-mesh wire mesh. They were 0.02% and 0.04% (dry weight percent), respectively. Comparative Example 1 A comparative composition (1) was obtained in the same manner as in Example 1 except that ethylene glycol monobutyl ether acetate was not used at all. Comparative Examples 2 to 3 Comparative compositions were prepared in the same manner as in Example 1, except that 8 times each of ethylene glycol monobutyl ether (Comparative Example 2) and diethylene glycol monoethyl ether (Comparative Example 3) were used in place of ethylene glycol monobutyl ether acetate. Products (2) and (3) were obtained. Ethylene glycol monobutyl ether and diethylene glycol monoethyl ether at 20℃
The solubility in 100 g of water is 50 g or more, and the amount of aggregates generated when blended with polymer emulsion (1) is 1.24% and 0.98%, respectively, based on the adhesive composition.
It was %. Example 4 An adhesive composition (4) was obtained in the same manner as in Example 2, except that the amount of ethylene glycol monoethyl ether acetate was changed to 24 parts. Comparative Examples 4-5 Comparative compositions (4)-( 5) was obtained. Comparative Example 6 A comparative composition (6) was obtained in the same manner as in Example 1, except that no tackifier was used and the number of ethylene glycol monobutyl ether acetate added was changed to 5 parts. Example 5 Using adhesive compositions (1) to (4) obtained in Examples 1 to 4 and Comparative Examples 1 to 6 and compositions for comparative examples (1) to (6), an adhesion test was conducted by the following method. The drying properties, adhesion, heat resistance, and water resistance were investigated. (1) After applying 200g/ ^m2 of each composition onto a slate board, leave it at 20°C and 65% RH, and the applied material changes from milky white to transparent and becomes semi-dry to the point where it can be bonded. It was evaluated based on the time (minutes) until the end of the test. (2) Adhesion (low temperature) 200 g/m ² of each composition was applied onto a slate board at a temperature of 5°C. Next, after 30 minutes of open time, the foaming ratio was 30x.
10 mm thick polyethylene foam was adhered using a 1 Kg/inch hand roller. Immediately after gluing
The 180° peel strength was measured. (Normal temperature) A similar test was conducted at 20°C and 65% RH. (3) Heat-resistant adhesion After applying 200 g/m ² of each composition onto a slate board and leaving it open for 30 minutes, 1 kg/m of polyethylene foam with a foaming ratio of 30 times and a thickness of 10 mm was applied.
Glued with an inch hand roller. Lamination is
The test was carried out at 20°C and 65% RH and cured for 7 days under the same conditions. The film was heated at 50° C. for 1 hour, and a vertical peel test was conducted under heating at a peel rate of 50 mm/min. (4) Water-resistant adhesive A test piece similar to that used in the heat-resistant adhesive test was immersed in water at 20°C for 7 days. This specimen was immediately subjected to a vertical peel test in a wet state. The test results of (1) to (4) above are shown in Table-1.

【table】

[Table] As is clear from the results in Table 1, water at 20℃
The adhesive composition of the present invention using an alkylene glycol derivative (C) with a solubility of 50 g or less per 100 g had excellent drying properties, low-temperature adhesion, heat-resistant adhesion, and water-resistant adhesion compared to other compositions. .

Claims (1)

[Scope of Claims] 1. A monomer consisting of 50 to 100% by weight of an acrylic ester having an alkyl group having 4 to 8 carbon atoms (a) and 0 to 50% by weight of other polymerizable monomers (b) Polymer emulsion (A) obtained by emulsion polymerization of ingredients 60~
95% by weight (in terms of non-volatile content), coumaron resin, phenol resin, terpene resin, terpene-
Tackifier (B) consisting of one or more selected from phenolic resin, petroleum resin, rosin resin, and their derivatives 5 to 40% by weight (in terms of non-volatile content)
(However, the total of non-volatile content of (A) and non-volatile content of (B) is 100
Weight%. ) and 100 parts by weight of an aqueous dispersion consisting of
An adhesive composition comprising 1 to 15 parts by weight of an alkylene glycol derivative (C) having a solubility in 100 g of water at 20° C. of 50 g or less. 2. The adhesive composition according to claim 1, wherein the alkylene glycol derivative (C) is alkylene glycol alkyl acetate.