JP2008031277A - One component type heat curable adhesive composition - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a one component type heat curable adhesive having adhesive force equal to a two component type epoxy adhesive to materials containing moisture or hygroscopic moisture. <P>SOLUTION: The heat curable adhesive composition comprises (component a) an OH-containing (meth)acrylate, (component b) a urethane (meth)acrylate, (component c) a poly(meth)acrylate-based polymer having 1-18C alkyl and (component d) a thermal reaction initiator and, in addition, (component e) a 1-18C alkyl (meth)acrylate. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a one-component thermosetting adhesive composition that exhibits high adhesion to materials containing moisture and moisture, such as tiles and earthenware.

  Since tiles and earthenware contain some moisture, the lipophilic adhesive has a weak adhesive force, and a hydrophilic adhesive must be used. In the one-pack type, vinyl acetate emulsion is produced and used in large quantities, but since it is not a curable type, it has poor water resistance and adhesive strength and cannot be used in fields requiring high adhesive strength. Moreover, since cyanoacrylate is cured with moisture, it may be applied to wet surfaces. However, cyanoacrylate is weak in water resistance and not impact resistant, so it cannot be used in fields requiring high adhesive strength. Therefore, a two-component type epoxy adhesive is used for bonding the tiles.

  Here, the epoxy adhesive has a high adhesive force, and strongly bonds even a material containing some moisture. However, since they are two liquids, they have to be mixed in small portions on site, and have the disadvantage that they must be discarded after the pot life. Furthermore, since epoxy resin is inferior in weather resistance, when used on the exterior surface in the construction field, there is a drawback of yellowing.

  Therefore, an object of the present invention is to provide a non-yellowing one-component adhesive having an adhesive force equivalent to that of a two-component epoxy adhesive to a material containing moisture.

  Here, in order to solve the above-mentioned problems, first, the present inventor studied using a hydroxyl group or carboxyl group-containing polar and highly hydrophilic monomer in order to adhere to a wet surface. However, when the monomer is used, the thermal initiator in the composition (a thermal initiator that decomposes at 100 ° C. or lower) crystallizes and precipitates as soon as it returns to room temperature even when heated and melted. The problem arises that the product cannot be commercialized due to separation. This is because the thermal reaction initiator is oleophilic and is essentially insoluble or insoluble in the polar and hydrophilic monomers containing the hydroxyl group or carboxyl group.

  In addition, when adding urethane (meth) acrylate oligomer as a component to improve weather resistance, in addition to adding a polymer compatible with the monomer as a component to make the adhesive strength equivalent to epoxy adhesive However, depending on the combination, it has been found that the same problem occurs.

  Therefore, the present invention provides a hydroxyl group-containing monomer as a main component in providing a thermosetting adhesive composition that exhibits high adhesion to a moisture-containing material that can be decomposed at 100 ° C. or lower and stored at room temperature. A specific problem is to provide a technology that allows a thermal initiator, a polymer compatible with a hydrophilic monomer, and a urethane (meth) acrylate oligomer to exist stably without degrading adhesive force And

  The patent documents listed below are known documents related to the present invention. Hereinafter, the contents thereof will be briefly described, and differences from the present invention will be described.

  Patent Document 1 discloses a resin composition for laminated glass that can be cured at room temperature and has little coloration over time. Specifically, this glass resin composition comprises <component 1> (meth) acrylate copolymer, <component 2> (meth) acrylate, <component 3> thermal reaction initiator, <component 4> thermosetting component. As a mercaptosilane compound. Here, the binding target of the resin composition is glass that is not in a wet state. Moreover, this resin composition is a mixed system of two or more component liquids in which component 3 + component 4 and the like are added to the binder component of component 1 + component 2 immediately before casting (upper right column on page 2). 5 to 6 lines, 2nd line to the lower right column 10 lines from the lower left column on page 5). Furthermore, this resin composition aims at curing at room temperature without applying heat (for example, the mercaptosilane compound of component 4 functions to enhance room temperature curability).

  Patent Document 2 discloses a liquid curable resin composition excellent in curability and durability and suitable as a coating material such as an optical fiber or a fiber optic tape core wire. Specifically, this liquid curable resin composition contains <Component 1> urethane (meth) acrylate, <Component 2> polymerizable monofunctional vinyl monomer, and <Component 3> polymerization initiator. Further, it is described that a curable polymer {polyester (meth) acrylate and the like} may be blended in addition to the above essential components (paragraph number 0034). Here, the binding target of the resin composition is an optical fiber that is not in a wet state.

  Patent Document 3 discloses a curable resin composition (polymerizable liquid resin) capable of obtaining resin mortar and resin concrete having good workability and room temperature curability. Specifically, this curable resin composition contains <component 1> a monomer component such as (meth) acrylic acid, and <component 2> a resin soluble in the monomer component. Here, in addition to the above essential components, it is described that reactive oligomers such as urethane (meth) acrylate may be added as long as they can be dissolved in component 1 (paragraph 0012).

Thus, although there exists prior art that discloses a partial combination of a plurality of components constituting the adhesive according to the present invention, none of them are adhesives for materials containing moisture. Moreover, the point of the present invention is that when a plurality of suitable components selected to obtain an adhesive for moisture-containing material that exhibits an adhesive force equivalent to that of an epoxy adhesive is present in the same system, the compatibility is improved. In the situation where two poor combinations occur, the problem is solved by adding only one compatibilizing agent. In the prior art, only those with good compatibility are combined. As is clear, no consideration is given to any prior art.
JP-A-2-97439 JP-A-5-163318 Japanese Patent Laid-Open No. 10-287716

  As a result of diligent research, the present inventor has found that a predetermined component functions as a compatibilizer between a hydroxyl group-containing (meth) acrylate monomer and a thermal reaction initiator, and is compatible with a predetermined polymer (for example, polymethyl metathesis). The present invention has been completed by finding that it functions as a compatibilizer between an acrylate) and a urethane (meth) acrylate oligomer.

The present invention (1) comprises (component a) a hydroxyl group-containing (meth) acrylate,
(Component b) Urethane (meth) acrylate,
(Component c) A thermosetting adhesive composition having a poly (meth) acrylate polymer having 1 to 18 carbon atoms in the alkyl group, and (Component d) a thermal reaction initiator,
(Component e) A thermosetting adhesive composition further containing an alkyl (meth) acrylate having 1 to 18 carbon atoms in the alkyl group.

This invention (2), (1) The sum total of the component a and the component e is 60 mass% or more with respect to the total amount of the components ac and e, and
(2) The mass ratio of component a / component e is 3-1;
It is the thermosetting adhesive composition of the said invention (1).

  In the present invention (3), the component a is 30 to 75% by mass, the component b is 5 to 35% by mass, the component c is 5 to 15% by mass, and the component e is based on the total amount of the components a to c and e. Thermosetting of the said invention (1) or (2) which is 15-30 mass% and contains 0.1-5 mass parts of component d with respect to 100 mass parts of total amounts of components ac and e. This is a mold adhesive composition.

  The present invention (4) is the thermosetting adhesive composition according to any one of the inventions (1) to (3), further comprising (component f) a silicic anhydride-based filler.

  This invention (5) is a thermosetting adhesive composition of the said invention (4) which contains the component f 50 mass parts or less with respect to 100 mass parts of total amounts of the components ac and e.

  This invention (6) is any one of said invention (1)-(5) whose component a is 1 or more types selected from 2-hydroxyethyl (meth) acrylate and 2-hydroxypropyl (meth) acrylate. One thermosetting adhesive composition.

  This invention (7) is the thermosetting adhesive composition of the said invention (6) whose component a is 2-hydroxyethyl methacrylate.

  The present invention (8) is the invention (1) wherein the component c is at least one selected from homopolymers and copolymers containing 80% or more of (meth) acrylates having 1 to 2 carbon atoms, and modified products thereof. The thermosetting adhesive composition according to any one of (1) to (7).

  The present invention (9) is the thermosetting adhesive composition according to any one of the inventions (1) to (8), wherein the component d is lauroyl peroxide.

  The present invention (10) is the thermosetting adhesive composition according to any one of the inventions (1) to (9), wherein the component e is an alkyl (meth) acrylate having 4 to 12 carbon atoms.

  This invention (11) is the thermosetting adhesive composition of the said invention (10) whose component e is a C4-C8 alkyl (meth) acrylate.

  The “thermosetting adhesive composition” according to the present invention has (component a) hydroxyl group-containing (meth) acrylate, (component b) urethane (meth) acrylate, and (component c) alkyl group having 1 to 18 carbon atoms. A thermosetting adhesive composition comprising a poly (meth) acrylate-based polymer and (component d) a thermal reaction initiator, wherein (component e) compatibilizers of component a and component d and components b and c As a compatibilizing agent, an alkyl (meth) acrylate having an alkyl group having 1 to 18 carbon atoms is further contained. Thus, this composition has five components as essential components. Here, first, two systems having poor compatibility are combined {4 material: hydroxyl group-containing (meth) acrylate / thermal reaction initiator, urethane (meth) acrylate / polymethyl methacrylate polymer) with an epoxy adhesive Equivalent adhesive strength is expressed. Moreover, the alkyl (meth) acrylate having 1 to 18 carbon atoms of the alkyl group functions as a common compatibilizing agent for two incompatible systems or two systems having poor compatibility. Hereinafter, each component will be described in detail.

  First, the hydroxyl group-containing (meth) acrylate according to “component a” is not particularly limited as long as it is a (meth) acrylate having a hydroxyl group in the molecule. For example, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl ( Examples include meth) acrylate, 3-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, and the like. Here, since the adhesive force tends to improve as the hydrocarbon chain of the ester portion becomes shorter, from the viewpoint of obtaining higher adhesive force, 2-hydroxyethyl (meth) acrylate or 2-hydroxy hydrocarbon chain having a shorter hydrocarbon chain is used. Hydroxypropyl (meth) acrylate is preferred. In addition, since the reaction rate of acrylate is higher than that of methacrylate, it is advantageous to use acrylate because the curing time is shortened. Note that acrylates with short hydrocarbon chains are highly irritating to the skin and have strong odors upon heating. Therefore, 2-hydroxyethyl methacrylate and 2-hydroxypropyl methacrylate are most preferable from the viewpoints of reaction rate and skin irritation. If the working environment is maintained, 2-hydroxyethyl acrylate and 2-hydroxypropyl acrylate can also be preferably used.

  Next, the urethane (meth) acrylate according to “component b” is not particularly limited as long as it is a reactive (meth) acrylate oligomer having a urethane skeleton. Here, a suitable urethane (meth) acrylate is an oligomer having a number average molecular weight of 500 to 20000 (more preferably 1000 to 15000). Furthermore, a suitable urethane (meth) acrylate is an oligomer having a viscosity (measured with a B-type viscometer) of 100 to 30000 mPa · s (60 ° C.). In addition, the number of (meth) acryloyl groups is preferably 2 to 6. Here, the component is known as a material having good weather resistance, capable of thermosetting, and satisfying moisture resistance, acid resistance, alkali resistance, chemical resistance, and the like. In addition, as the said component, in order to avoid yellowing, it is preferable to select what does not contain a benzene ring. Specifically, “Art Resin Series” (for example, UN-8030X, UN-9000PEP) from Negami Kogyo Co., Ltd., “CN Series” (for example, CN980, CN996) from Sartomer Japan, Inc., UV curing by Nippon Synthetic Chemical. It is available under the trade name “Shikou Series”, which is a mold resin.

  Next, the poly (meth) acrylate polymer having 1 to 18 carbon atoms in the alkyl group according to “Component c” is not particularly limited, but those having a weight average molecular weight of 50,000 to 2,000,000 are suitable. By adding such a component, it becomes possible to obtain an adhesive force equivalent to that of an epoxy adhesive, which cannot be obtained only by combining the component a and the component b. Here, although the said polymer melt | dissolves or disperses | distributes in the component a, it is not stably compatible with the component b (For this reason, the addition of the component e mentioned later is needed).

  Here, the preferable “component c” is a homopolymer or copolymer containing 80% or more of (meth) acrylate having 1 to 2 carbon atoms, or a modified product thereof. As the modified product, these polymers whose molecules or molecular ends are modified with epoxy or maleic acid can be used. Particularly preferred “component c” is polymethyl methacrylate and derivatives / modified products thereof. As these polymers, Parapet (registered trademark) {manufactured by Kuraray Co., Ltd.}, Dianar (registered trademark) LP3106 (manufactured by Mitsubishi Rayon Co., Ltd.), Zefiac F340A (manufactured by Zeon Kasei Co., Ltd.), Hyperl M4202 (Negami) Industrial Co., Ltd.} and the like.

  Next, the thermal reaction initiator according to “component d” is not particularly limited as long as it can be stored at room temperature, does not contain a benzene ring (because of causing yellowing), and has a half-life of 1 minute. A temperature of 90 to 160 ° C. is preferred. In particular, the thing of 100-130 degreeC is suitable. Here, since the said component is lipophilic, it does not melt | dissolve in the component a (For this reason, the addition of the component e mentioned later is needed). There are many types of the components, but as a composition in which the adhesive composition can be stored at room temperature and almost completely decomposes at 100 ° C. for 30 minutes, paroyl TCP (di-4-t-butylcyclohexyl par Oxydicarbonate), paroyl L (lauroyl peroxide), B.I. P. O. (Benzoyl peroxide), perhexa C (C) {1,1-di (t-butylperoxy) cyclohexane} {all manufactured by NOF Corporation} and the like. Of these, lauroyl peroxide is most preferred.

  Next, the alkyl (meth) acrylate having 1 to 18 carbon atoms of the alkyl group according to “component e” functions as a compatibilizer between the hydroxyl group-containing (meth) acrylate monomer and the thermal initiator, and the monomer It also functions as a compatibilizing agent for a specific polymer (for example, polymethyl methacrylate or a modified product thereof) compatible with the urethane (meth) acrylate oligomer. That is, this component is effective as a common compatibilizing agent for two systems having poor compatibility. More preferred are alkyl (meth) acrylates having 4 to 12 carbon atoms in the alkyl group, and most preferred are alkyl (meth) acrylates having 4 to 8 carbon atoms in the alkyl group. For example, 2-ethylhexyl (meth) acrylate, n-hexyl (meth) acrylate, isoamyl (meth) acrylate, n-amyl (meth) acrylate, n-butyl (meth) acrylate, isobutyl (meth) acrylate, t- Examples include butyl (meth) acrylate.

  The essential components of the thermosetting adhesive composition have been described in detail above. Next, the thermosetting adhesive composition will be described.

  First, the content of “component a” is preferably 30 to 75 mass% with respect to the total amount of components a to c and e. If it is less than this, the adhesive strength is lowered. Moreover, when it exceeds this range, water resistance will fall.

  Next, the content of “component b” is preferably 5 to 35% by mass, more preferably 10 to 30% by mass, and 15 to 20% by mass with respect to the total amount of components a to c and e. % Is particularly preferred. If it is less than this, the adhesive force tends to decrease. Moreover, even if it exceeds this range, the adhesive properties tend to decrease.

  Next, the content of “component c” is preferably 5 to 15 mass%, more preferably 6 to 10 mass%, and 6 to 7 mass based on the total amount of components a to c and e. % Is particularly preferred. If it is less than this, the adhesive force tends to decrease. Moreover, even if it exceeds this range, a viscosity will become high, workability | operativity will be bad, and an adhesive characteristic will also fall.

  Next, the content of “component d” is preferably 0.1 to 5 parts by mass and more preferably 0.3 to 3 parts by mass with respect to 100 parts by mass of the total amount of components a to c and e. And 0.5 to 2.5 parts by mass is particularly suitable. If it is less than this, it tends to be insufficiently cured. If this range is exceeded, foaming may occur.

  Next, the content of “component e” is preferably 15 to 30% by mass, more preferably 20 to 28% by mass, and more preferably 25 to 26% by mass with respect to the total amount of components a to c and e. % Is particularly preferred. If it is less than this, compatibility will worsen. Moreover, even if it exceeds this range, the adhesive properties tend to decrease.

  Here, the sum of component a and component e is 60% by mass or more with respect to the total amount of components a to c and e, and the mass ratio of component a / component e is 3 to 1. Is preferred. Moreover, the sum total of the component a and the component e is 65-80 mass% with respect to the total amount of the components ac and e, and the mass ratio of the component a / component e is 2.8-1.1. Is more preferred. When it is within the range, the function of the component e as a compatibilizing agent can be sufficiently exhibited.

  The thermosetting adhesive composition may contain other components as necessary. For example, for the purpose of adjusting the viscosity, (Component f) a filler may be contained (for example, silicic anhydride-based filler). Here, content of the said component is about 0-50 mass parts (suitably 1-50 mass parts) with respect to 100 mass parts of total amounts of component ac and e. If it is this range, far modification can be provided and fluidity | liquidity can be suppressed. Moreover, you may contain fillers other than a silicic acid type filler, a polymerization inhibitor, a flame retardant, etc. as other arbitrary ingredients.

  Next, the thermosetting adhesive composition preferably has thixotropic properties in order to prevent “sagging” of the adhesive. Here, it is preferable that this composition has a viscosity in a B-type viscometer of 500 to 500,000 mPa · s at 25 ° C. and a thixotropic coefficient of 1.1 or more. Here, the viscosity of the composition is a viscosity at a rotational speed of 2 to 20 rpm measured using a B-type viscometer (model: BH type, rotor No. 6 or 7}. Further, thixotropy of the composition is used. The coefficient (TI value) is the apparent viscosity of the present composition measured at the same rotational speeds of 2 rpm and 20 rpm, and the ratio η2 / η20 of η2 and η20.

  Next, this thermosetting type adhesive composition can be manufactured by mixing the said each component according to a normal method. It is preferable to prevent bubbles from entering during the production of the composition. In addition, when air bubbles enter the composition, it is preferable to defoam according to a well-known method.

  Hereinafter, the present invention will be described more specifically with reference to examples.

Test method: Adhesive strength is measured based on the quality standard for bonded tiles (National Tile Industry Association Bond Quality Tile Quality Standards Review Committee).
Test piece preparation method: A test piece is prepared by bonding tiles each having a thickness of 5 mm and a width of 45 mm, each having a side cut to 45 °, and bonded to each other at an angle of 90 degrees with an adhesive. Specifically, the two test pieces cut at 45 degrees are butted together, the part that contacts the frame is masked with masking tape at a flat place, the adhesive is applied to the bonded part, and the test piece is placed on the right-angled frame. (Tile) is placed and thermally cured at 90 ° C. for 30 minutes. Application amount: 0.2 to 0.5 g / 4.5 cm ² .
Test method / Evaluation method: A test piece is installed in a mountain shape on a compression tester, and compressed from above to perform a destructive test. Five test pieces are used for each type. A sample having an average adhesive strength of 200 N / cm ² was evaluated as ◯.

Effects of the invention: 1 liquid, can be stored at room temperature, can be cured at 100 ° C. or lower, has an epoxy equivalent adhesive force, and no yellowing. No need for on-site mixing and zero disposal. High value in the construction industry. The tile industry currently uses a two-part epoxy adhesive, and because of the two-part mix, workability is poor due to on-site mixing. After mixing, excess adhesive can only be discarded. If the weathering is not good and it turns yellow within 10 years after the tile construction, it will be necessary to reconstruct it.

Claims (11)

(Component a) Hydroxyl group-containing (meth) acrylate,
(Component b) Urethane (meth) acrylate,
(Component c) A thermosetting adhesive composition having a poly (meth) acrylate polymer having 1 to 18 carbon atoms in the alkyl group, and (Component d) a thermal reaction initiator,
(Component e) A thermosetting adhesive composition further containing an alkyl (meth) acrylate having 1 to 18 carbon atoms in the alkyl group. (1) The sum of component a and component e is 60% by mass or more based on the total amount of components a to c and e, and
(2) The mass ratio of component a / component e is 3-1;
The thermosetting adhesive composition according to claim 1.   Component a is 30 to 75% by mass, Component b is 5 to 35% by mass, Component c is 5 to 15% by mass, and Component e is 15 to 30% by mass with respect to the total amount of components a to c and e. And the thermosetting adhesive composition of Claim 1 or 2 which contains 0.1-5 mass parts of components d with respect to 100 mass parts of total amounts of components ac and e. The thermosetting adhesive composition according to any one of claims 1 to 3, further comprising (component f) a silicic anhydride-based filler.   The thermosetting adhesive composition of Claim 4 which contains 50 mass parts or less of component f with respect to 100 mass parts of total amounts of component ac and e.   The thermosetting adhesive composition according to any one of claims 1 to 5, wherein component a is one or more selected from 2-hydroxyethyl (meth) acrylate and 2-hydroxypropyl (meth) acrylate. .   The thermosetting adhesive composition according to claim 6, wherein component a is 2-hydroxyethyl methacrylate.   The component c is at least one selected from homopolymers and copolymers containing 80% or more of (meth) acrylates having 1 to 2 carbon atoms and modified products thereof. Thermosetting adhesive composition.   The thermosetting adhesive composition according to any one of claims 1 to 8, wherein component d is lauroyl peroxide.   The thermosetting adhesive composition according to any one of claims 1 to 9, wherein the component e is an alkyl (meth) acrylate having 4 to 12 carbon atoms. The thermosetting adhesive composition of Claim 10 whose component e is a C4-C8 alkyl (meth) acrylate.