JP7611730B2 - Two-component adhesive composition - Google Patents

Description

The present invention relates to a two-part adhesive composition that contains a modified silicone resin, which is a compound having a hydrolyzable silyl group, and an epoxy resin.

When finishing the walls of a building, a method is used in which interior panels such as decorative panels are fixed to a base material such as plasterboard with adhesive. In this case, it is necessary to temporarily fix the interior panel to the base material until the adhesive hardens to prevent the interior panel from shifting or falling off. A common method is to use both double-sided adhesive tape and an adhesive, temporarily fixing the panel with the double-sided adhesive tape and then permanently fixing it with the adhesive.

This method allows interior panels to be stably fixed, but if double-sided adhesive tape is used for temporary fixing, it is difficult to remove once applied, making fine alignment surprisingly difficult. In addition, it is time-consuming to peel off the release paper from the adhesive tape, which becomes waste and makes cleanup difficult, creating problems in terms of workability during construction.

To address these issues, a bonding method has been proposed that uses adhesive A containing a first polymer having an alkyldialkoxysilyl group and adhesive B containing a second polymer having a trialkoxysilyl group at the molecular end as an adhesive that does not require temporary fixing with double-sided adhesive tape (Patent Document 1). However, this method is time-consuming in that two types of adhesives must be applied separately, and there is also the problem that the adhesive strength during temporary fixing is prone to vary depending on the application method because the pot life varies depending on the mixing ratio of the two types. For this reason, there has been a demand for an adhesive that can obtain stable adhesion in a short time after mixing the two liquids and can fix interior panels without temporary fixing using double-sided tape or the like.

Patent No. 5335507

The objective of the present invention is to provide a two-component adhesive composition that cures in a short time after mixing the base agent and the curing agent, and has stable adhesive strength even without temporary fixation with double-sided adhesive tape, and an adhesive construction method using the same.

In order to solve the above problems, the invention of claim 1 provides an adhesive composition comprising a base agent (A) containing a compound (a) having a hydrolyzable silyl group, an epoxy resin (b) and water (c), and a curing agent (B) containing a tertiary amine (d) and a curing catalyst (e) for said (a) , wherein said (a) contains a (meth)acrylic polymer having a trimethoxysilyl group and a polypropylene oxide having a trimethoxysilyl group , and the amount of (a) in said (A) is 60 to 97% by weight based on the total amount of solids .

The invention of claim 2 provides the adhesive composition of claim 1, characterized in that the amount of (b) in (A) is 2 to 30% by weight based on the total solid content.

The invention of claim 3 provides the adhesive composition according to claim 1 or 2, characterized in that (B) further contains a plasticizer (f).

A fourth aspect of the present invention provides the adhesive composition according to the third aspect, wherein the (f) is a (meth)acrylic polymer.

The invention of claim 5 provides a method for adhering an interior panel material to a base material without temporary fixing, using the adhesive composition of any one of claims 1 to 4.

The two-part adhesive composition of the present invention cures in a short time after mixing the base agent and the curing agent, and has stable adhesive strength, making it useful as an adhesive that can fix interior panels to base materials without the need for temporary fixation with double-sided adhesive tape.

The main component (A) of the adhesive composition of the present invention contains a compound (a) having a hydrolyzable silyl group, an epoxy resin (b), and water (c), and the curing agent (B) contains a tertiary amine (d) and a curing catalyst (e). In this specification, (meth)acrylate includes both acrylate and methacrylate.

The compound (a) having a hydrolyzable silyl group used in the present invention is the main resin constituting the main agent (A) and is blended for the purpose of achieving high initial adhesion and rapid curing. Examples of the main skeleton include (meth)acrylic polymer, polyalkylene oxide, polyisobutylene, etc., but at least the main skeleton is a (meth)acrylic polymer structure and includes a compound having a trimethoxysilyl group as the hydrolyzable silyl group.

In the above (a), in order to lower the viscosity after mixing the base agent (A) and the curing agent (B) and at the same time improve adhesion to the substrate, it is preferable to use a compound having a polyalkylene oxide main skeleton in addition to the main skeleton of the (meth)acrylic polymer structure. Examples of polyalkylene oxides include polyethylene oxide and polypropylene oxide. Commercially available products include MA451 and MA480 (product names: manufactured by Kaneka Corporation), which are mixtures of a (meth)acrylic polymer having a trimethoxysilyl group and a polypropylene oxide having a trimethoxysilyl group.

The amount of (a) is preferably 50 to 97% by weight, more preferably 60 to 95% by weight, and particularly preferably 70 to 90% by weight, based on the total solid content of the main component (A). By making it 50% by weight or more, it is possible to ensure sufficient initial tackiness to the finger and fast curing properties, and by making it 97% by weight or less, it is possible to ensure sufficient planar tensile strength and workability.

The epoxy resin (b) used in the present invention is blended for the purpose of increasing the hardness of the adhesive cured product and improving its planar tensile strength. Examples include aromatic epoxy resins such as bisphenol type and their hydrogenated products, alicyclic epoxy resins, aliphatic chain epoxy resins, isocyanurate type epoxy resins, glycidyl ester type epoxy resins, and glycidyl amine type epoxy resins. Among these, bisphenol type epoxy and aliphatic chain epoxy resins are preferred because of their low viscosity and good compatibility with (a).

As the bisphenol type epoxy, bisphenol A type epoxy, which has an epoxy equivalent of 170 to 200 and is liquid at room temperature, and bisphenol F type epoxy, which has an epoxy equivalent of 160 to 185 and is liquid at room temperature, are particularly preferred. In addition, examples of aliphatic chain epoxy resins include C4 to C8 diglycidyl ethers, and among these, hexamethylene diglycidyl ether is particularly preferred.

When (b) is blended with the hardener (B), the hardener (d) for (b) is blended with the base agent (A). In this case, the reaction between (a) and (d) proceeds in the presence of water (c) and thickens, resulting in a decrease in the shelf life of the base agent (A). Therefore, (b) must be blended with the base agent (A).

The amount of (b) is preferably 2 to 30% by weight, more preferably 3 to 25% by weight, and particularly preferably 8 to 18% by weight, based on the total solid content of the main component (A). By making it 2% by weight or more, sufficient planar tensile strength can be ensured, and by making it 30% by weight or less, sufficient compatibility and fast curing properties can be ensured.

The water (c) used in the present invention is blended to accelerate the curing speed when the base agent (A) and the curing agent (B) are mixed, to develop adhesive strength in a short time, and to improve deep curing properties. Examples include ion-exchanged water, distilled water, city water, and hydrous gel. Adding (c) to the curing agent (B) improves deep curing properties, but the catalyst reacts easily with water, and tends to hydrolyze, especially when a tin-based catalyst is used, resulting in reduced storage stability and making it unsuitable.

The amount of (c) is preferably 0.3 to 5% by weight, more preferably 0.5 to 2.5% by weight, and particularly preferably 0.8 to 1.5% by weight, based on the total solid content of the main component (A). By making it 0.3% by weight or more, it is possible to ensure sufficient rapid curing and early development of adhesive strength, and by making it 5% by weight or less, sufficient storage stability can be ensured.

The tertiary amine (d) used in the present invention is blended as a curing agent for (b) blended with the main agent (A). By using a tertiary amine, a cured product with high rigidity, high strength, and high elongation can be obtained. For example, piperidine, pyridine, benzyldimethylamine, 2-(dimethylaminomethyl)phenol, triethylenediamine, dimethylcyclohexylamine, dimethylbenzylamine, dimethylhexylamine, dimethylaminophenol, dimethylamino p-cresol, piperidine, 1,4-diazadicyclo[2.2.2]octane, 2,4,6-tris(dimethylaminomethyl)phenol, 1.8-diazabicyclo[5.4.0]undecene-1, etc. can be mentioned, and they can be used alone or in combination of two or more kinds. Among these, 2,4,6-tris(dimethylaminomethyl)phenol is preferred because it has good reactivity, high adhesive performance, and is well-balanced in terms of availability and cost.

The amount of (d) is preferably 1 to 120 parts by weight, more preferably 5 to 100 parts by weight, and particularly preferably 10 to 80 parts by weight, per 100 parts by weight of (b) mixed into the main agent (A). By using an amount of 1 part by weight or more, it is possible to ensure excellent curing properties after mixing, and by using an amount of 120 parts by weight or less, sufficient storage stability can be ensured. A commercially available product is HISCAT HI-54K (product name: 2,4,6-tris(dimethylaminomethyl)phenol, manufactured by KEUM JUNG Co., Ltd.).

The curing catalyst (e) used in the present invention is blended for the purpose of promoting the hydrolysis reaction of the alkoxy group, which is the hydrolyzable silyl group of (a) blended in the main agent (A), and improving the curing speed. Specific examples include metal compounds, amine compounds, carboxylic acids, etc., but metal compounds are preferred in terms of catalytic activity. Metal compounds include, for example, tin-, zirconium-, titanium-, aluminum-, and bismuth-based compounds, which can be used alone or in combination of two or more. Among these, tin-based compounds are preferred in terms of their high activity as silanol condensation catalysts, and dibutyltin-based compounds are particularly preferred. A commercially available product is Neostan U-220H (trade name: dibutyltin diacetylacetonate, manufactured by Nitto Kasei Co., Ltd.).

The amount of (e) is preferably 0.1 to 8 parts by weight, more preferably 0.3 to 5 parts by weight, and particularly preferably 0.5 to 3 parts by weight, per 100 parts by weight of (a) contained in the main agent (A). By using an amount of 0.1 part by weight or more, sufficient curing properties can be expected, and by using an amount of 8 parts by weight or less, sufficient adhesive strength and sufficient usable time for working can be ensured.

The curing agent (B) of the present invention may further contain a plasticizer (f) to improve workability and adjust the hardness of the cured product. The plasticizer is preferably liquid at 25°C, and examples of such plasticizers include phthalate esters, aliphatic esters, polyesters, polyalkylene glycol esters, polyether polyols, epoxy, and vinyl polymers. These may be used alone or in combination of two or more types. Among these, polymer plasticizers are preferred because they can adjust the mechanical properties of the cured product, such as tensile strength and elongation, and they suppress bleeding compared to low molecular weight plasticizers, allowing the initial physical properties to be maintained for a long period of time.

As the polymer plasticizer, vinyl polymers are preferred because of their excellent weather resistance and heat resistance, and (meth)acrylic polymers are particularly preferred because of their excellent compatibility with (a). The weight average molecular weight (hereinafter Mw) is preferably 500 to 6000, and more preferably 1000 to 3000. The viscosity at 25°C is preferably 100 to 3000 mPa·s, and more preferably 200 to 2000 mPa·s. By keeping the viscosity within this range, bleeding can be suppressed and the initial physical properties can be maintained for a long period of time, and the compatibility with other components is good, making it easy to achieve an appropriate viscosity suitable for workability.

The amount of (f) can be adjusted as desired to suit workability, but can be, for example, 0 to 150 parts by weight per 100 parts by weight of (a) contained in the main agent (A), preferably 30 to 130 parts by weight, and more preferably 50 to 120 parts by weight. Commercially available (meth)acrylic polymers include ARUFON UP-1000 (product name: manufactured by Toa Gosei Co., Ltd., Mw 3000, viscosity 1000 mPa·s) and UP-1020 (product name: manufactured by Toa Gosei Co., Ltd., Mw 1500, viscosity 400 mPa·s).

Tackifiers, thixotropic agents, adhesion promoters, antioxidants, leveling agents, defoamers, thickeners, suspending agents, antibacterial agents, inorganic fillers, organic fine particles, etc. may be added to the composition of the present invention as necessary, provided that the properties are not impaired.

The base agent (A) and hardener (B) of the composition of the present invention are mixed immediately before use. Although the composition has the characteristic of a very fast curing speed, its usable time is relatively short, so it is preferable to use a two-liquid mixing and dispensing device such as a static gun at the work site. By using such an application device that can automatically mix a fixed amount, workability at the work site can be significantly improved.

When using the present invention to bond interior panels such as decorative boards to base materials such as gypsum boards, calcium silicate boards, mortar surfaces, and plywood, a mixture of the base agent (A) and the hardener (B) is applied to one of the adherends, and the two are quickly bonded together. The amount of application is preferably 100 to 400 g/ ^m2 , and more preferably 150 to 250 g/ ^m2 . In this case, if the weight per area of the interior panel to be bonded is 1.0 g/ ^cm2 or less, it is possible to sufficiently bond the panel without temporary fixing using a double-sided adhesive tape. When bonding without temporary fixing, the weight per area of the adherend is preferably 0.95 g/cm2 or ^less , and more preferably 0.90 g/cm2 or ^less .

The present invention will be described in more detail below with examples and comparative examples, but these are concrete examples and are not intended to be limiting. Unless otherwise specified, measurements were taken at 23°C and 50% relative humidity. The units in the recipe table are parts by weight.

Example 1
On the main component (A) side, MA451 (trade name: manufactured by Kaneka Corporation, a mixture of a (meth)acrylic polymer having a trimethoxysilyl group and a polypropylene oxide having a trimethoxysilyl group) was used as (a), bisphenol A type epoxy (epoxy equivalent: 184 to 194, liquid at room temperature) was used as (b), and water was used as (c). On the curing agent (B) side, HISCAT HI-54K (trade name: manufactured by Keum Jung Corporation, 2,4,6-tris(dimethylaminomethyl)phenol) was used as (d), U-220H (trade name: manufactured by Nitto Kasei Corporation, dibutyltin diacetylacetonate) was used as (e), and UP-1020 (trade name: manufactured by Toa Gosei Co., Ltd., acrylic polymer, Mw 1500, viscosity 400 mPa·s) was used as (f). Each was added to a planetary mixer in the amounts shown in Table 1 and stirred until uniform. Thereafter, the mixture was degassed under reduced pressure to obtain the base resin (A) and the curing agent (B) of Example 1.

Examples 2 to 6
In addition to the materials used in Example 1, bisphenol F type epoxy (epoxy equivalent: 165 to 180, liquid at room temperature) and hexamethylene diglycidyl ether were used as (b), and the base material (A) and the curing agent (B) of Examples 2 to 6 were obtained in the same manner as in Example 1.

Comparative Examples 1 to 9
In addition to the materials used in the examples, SAX-580 (product name: polypropylene glycol having a trifunctional trimethoxysilyl group, manufactured by Kaneka Corporation) and EST-280 (product name: polypropylene glycol having a bifunctional trimethoxysilyl group, manufactured by Kaneka Corporation) were used as (a) in the amounts shown in Table 2, and the base material (A) and the curing agent (B) of Comparative Examples 1 to 9 were obtained in the same manner as in the examples.

Table 1

Table 2

Evaluation items and evaluation methods

Compatibility: The compatibility of the base agent (A) and the curing agent (B) was checked when they were prepared, and the condition was visually checked 30 minutes after preparation. Good compatibility was marked with an O, and separation or whitening was marked with an X.

Storability: The base agent (A) and hardener (B) were stored separately in a sealed container without being mixed, and left to stand for two weeks in an atmosphere of 40°C. After that, the base agent and hardener were mixed, and if there was no difference in the initial hardening time and no increase in viscosity was observed in either agent, it was marked as ◯, and if there was a delay in hardening or an increase in viscosity, it was marked as ×.

Initial adhesive strength: The base agent (A) and hardener (B) were mixed and applied, and the adhesive was checked for adhesiveness by touch 10 minutes after hardening. If there was adhesive strength, it was marked with a circle, and if there was no adhesive strength or the adhesive strength was extremely weak, it was marked with an X.

Curing time: The base agent (A) and curing agent (B) are mixed and applied in a bead shape with a diameter of 3.5 mm, and left to stand in an atmosphere of 23°C and 50% relative humidity. After a certain time has passed, the cross section is cut with a cutter. If the time required for curing to the inside is within 5 minutes, it is marked as ○, and if it exceeds 5 minutes, it is marked as ×.

Plane tensile strength: A flexible board conforming to JIS A 5430 was used as the base material, and 3 mmt x 40 mm x 40 mm AICA CERAALL FKM6000ZMN (product name: Aica Kogyo Co., Ltd., melamine resin-based non-flammable decorative board) was used as the surface material. The adhesive was mixed and applied in a bead shape with a diameter of 3.5 mm to the base material, which was then attached and left to cure for one week in an atmosphere of 23°C x 50% RH to prepare a test specimen. The plane tensile strength was then measured using a Construction Research Institute-type tensile tester, with 0.2 MPa or more marked as ○ and less than 0.2 MPa marked as ×. Measurements were taken from n=3, and the average value was used.

Evaluation results <br/> Table 3

Table 4

The examples were good with no problems in terms of compatibility, storage stability, initial adhesion, curing time, and flat tensile strength.

On the other hand, Comparative Example 1, which did not contain (e), and Comparative Example 3, which did not contain (c), were inferior in initial adhesion and curing time, Comparative Example 2, which did not contain (d), were inferior in initial adhesion, curing time, and flat tensile strength, and Comparative Example 5, which did not contain (b), had low flat tensile strength. Comparative Examples 4 and 6, in which (C) and (b) were blended in the curing agent side, were inferior in storage stability, Comparative Example 7, which used (a) that did not contain an acrylic polymer skeleton, was inferior in initial adhesion, and Comparative Example 8 was also inferior in curing time, and none of them were suitable for the present invention.

Claims (5)

An adhesive composition comprising: a base agent (A) containing a compound (a) having a hydrolyzable silyl group, an epoxy resin (b) and water (c); and a curing agent (B) containing a tertiary amine (d) and a curing catalyst (e) for said (a) , said (a) containing a (meth)acrylic polymer having a trimethoxysilyl group and a polypropylene oxide having a trimethoxysilyl group , said adhesive composition being characterized in that the blending amount of (a) in said (A) is 60 to 97% by weight based on the total solid content . The adhesive composition according to claim 1, characterized in that the amount of (b) in (A) is 2 to 30% by weight based on the total solid content. The adhesive composition according to claim 1 or 2, characterized in that (B) further contains a plasticizer (f). 4. The adhesive composition according to claim 3 , wherein the (f) is a (meth)acrylic polymer. A method for adhering an interior panel material to a base material without temporary fixing, using the adhesive composition according to any one of claims 1 to 4.