JPH1053754A - Adhesive composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an adhesive compsn. which does not discolor a decorative vinyl chloride resin sheet by combining a major component contg. a specific polyester urethane resin, a specific tackifying resin, and an imidazole compd. with an isocyanate-contg. curative. SOLUTION: This compsn. comprises a major component contg. 100 pts.wt. hydroxylated thermoplastic polyester urethane resin, 50-100 pts.wt. tackifying resin having no active hydrogen atom, and 0.5-10 pts.wt. imidazole compd. represented by the formula (wherein R<1> is H or a cyanohydrocarbon group; R<2> is a 1-6C hydrocarbon group; and R<3> is H or CH3 ) and a curative contg. an isocyanate compd. The polyester urethane resin is not specifically limited so long as it is one generally used as the main ingredient of an adhesive and having a mol.wt. of 100,000-400,000. A chroman resin, esp. its hydrogenated dervi., is perf. as the tackifying resin. An example of the isocyanate compd. is tolylene diisocyanate. The compsn. has a long pot life and a light cure rate. A major component contg. a tin salt is suitable for coating a decorative vinyl chloride resin sheet.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an adhesive composition, and more particularly, to blending a specific curing catalyst and a specific tackifying resin to maintain a long pot life after mixing a curing agent and to improve adhesion. When the curing speed after applying the agent is extremely fast and the adherend is a vinyl chloride resin film,
The present invention relates to an adhesive composition in which discoloration of a vinyl chloride resin due to light and heat is remarkably improved.

[0002]

2. Description of the Related Art A two-component mixed type solvent-based adhesive comprising a main component obtained by dissolving a thermoplastic polyester-based urethane resin in a solvent and a polyisocyanate curing agent is excellent in normal adhesive strength and heat resistance, and can be used for plastics, metals and woods. Widely used for bonding various materials.

In recent years, decorative sheet covering materials in which an adherend such as a medium fiberboard (MDF) is wrapped with a decorative sheet such as a vinyl chloride film using this adhesive have been widely used. Such decorative sheet covering materials are used for furniture, building materials, and the like because they impart various patterns to the surface of an inexpensive core material, a highly durable core material, and the like, and have added value such as luxury.

In order to improve the initial adhesiveness as an adhesive for such decorative sheet covering materials, a method has been proposed in which a phenol-modified xylene formaldehyde resin and / or a phenol-modified methylene formaldehyde resin is added as a tackifier to a main ingredient. (Japanese Patent Laid-Open No. 6-2002)
No. 29).

[0005] Although not for decorative sheet covering materials,
As an adhesive suitable for a composite panel for an inner wall of a vehicle, Japanese Patent Application Laid-Open No. 5-93180 discloses a two-component mixed solvent-based adhesive comprising a main agent comprising a urethane resin and an imidazole compound and a curing agent comprising an isocyanate compound. An agent is disclosed.

However, in the case of the above-mentioned two-liquid mixed type solvent-based adhesive, there is a problem that the curing speed is extremely slow in a low-temperature and low-humidity environment, so that long-term curing is required.

In general, a method of adding an organometallic catalyst, an amine catalyst or the like has been proposed for the purpose of controlling the pot life and the curing speed. However, the curing speed becomes slow even if the pot life becomes long. Under the condition of 5 ° C. or less, the curing hardly progresses and a heating curing curing furnace is required, so that disadvantages such as low productivity and high production cost arise. In addition, when the curing speed is increased, the pot life is shortened, and the workability is deteriorated, resulting in inconveniences such as poor adhesion and equipment trouble due to variations in the application amount.

Further, the two-component mixed type solvent-based adhesive disclosed in JP-A-5-93180 is suitable for bonding a vinyl chloride resin film. When the resin film is adhered, the vinyl chloride resin film may be discolored by light irradiation or heating at a high temperature for a long time.

[0009]

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and has as its object the long pot life, high curing speed after bonding, and low temperature (10 ° C.) curability. It is another object of the present invention to provide an adhesive composition which is excellent in heat resistance and does not cause discoloration of a vinyl chloride resin film even when subjected to long-time light irradiation or high-temperature heating.

[0010]

The adhesive composition according to the first aspect of the present invention (hereinafter referred to as the first aspect) is:
100 parts by weight of a hydroxyl group-containing thermoplastic polyester urethane resin, a tackifying resin containing no active hydrogen, 50 to 100
Parts by weight, a main agent containing 0.5 to 10 parts by weight of an imidazole compound represented by the following general formula (1), and a curing agent containing an isocyanate compound having two or more active isocyanate groups. It is characterized by.

The invention according to claim 2 of the present invention (hereinafter referred to as “second
The adhesive composition of the present invention comprises 100 parts by weight of a hydroxyl group-containing thermoplastic polyester urethane resin, 50 to 100 parts by weight of a tackifier resin containing no active hydrogen, and an imidazole compound 0 represented by the following general formula (1). .5-10
And a curing agent containing an isocyanate compound having two or more active isocyanate groups, and a main agent containing 0.5 to 5 parts by weight of divalent tin salts.

[0012]

Embedded image

In the general formula (1), R ¹ is a hydrocarbon group having a CN group or H, R ² is a hydrocarbon group having 1 to 6 carbon atoms, R is
³ represents CH ₃ or H.

Hereinafter, the present invention will be described in detail. The main agent used in the first invention contains a hydroxyl group-containing thermoplastic polyester urethane resin, a tackifier resin containing no active hydrogen, and an imidazole compound represented by the general formula (1).

The hydroxyl group-containing thermoplastic polyester urethane resin used in the main agent of the first invention is an elastomer having a urethane bond in a molecular chain, and is not particularly limited as long as it is used as a main component of this kind of adhesive. used. Specifically, adipic acid, azelaic acid,
Sebacic acid, terephthalic acid, isophthalic acid, phthalic acid,
An active hydroxyl group such as a saturated polyester resin obtained by a condensation reaction of a polybasic acid such as succinic acid and a dihydric alcohol such as propylene glycol, ethylene glycol, tetramethylene glycol, butanediol, hexanediol, and neopentyl glycol is used. Polyester resin, 4,4'-diphenylmethane diisocyanate (MDI), tolylene diisocyanate (TD
I), aromatic diisocyanates such as xylylene diisocyanate (XDI), aliphatic diisocyanates such as hexamethylene diisocyanate (HDI), lysine methyl ester diisocyanate (LDI), dicyclohexylmethane diisocyanate (HMDI), isophorone diisocyanate (IPDI), etc. Is a linear polymer obtained by subjecting an active isocyanate compound such as an alicyclic diisocyanate to an addition polymerization reaction.

As the hydroxyl group-containing thermoplastic polyester urethane resin, a hydroxyl group-containing thermoplastic polyester urethane resin obtained by reacting an aliphatic diisocyanate with a hydroxyl group-containing saturated polyester resin is preferable.

The weight average molecular weight of the hydroxyl group-containing thermoplastic polyester urethane resin is not particularly limited.
100,000 to 400,000 is preferable. If it is less than 100,000, the initial creep property of the obtained adhesive composition will decrease, and if it exceeds 400,000, the normal adhesive strength of the obtained adhesive composition will decrease.

The active hydrogen-free tackifying resin used in the main agent of the first invention refers to a tackifying resin substantially free of a hydroxyl group capable of reacting with an isocyanate group. Here, “does not contain” means that the active hydrogen group is not contained in the molecule and that a commercially available tackifier resin corresponding to active hydrogen is not blended. Such active hydrogen-free tackifying resins include coumarone polymer, coumarone-indene resin,
Coumarone-indene-styrene copolymer or the like is used. Among them, these hydrogenated products are preferable in that they are excellent in compatibility and do not contain active hydrogen.

Commercial products of the above-mentioned coumarone-indene-styrene copolymer include, for example, "Esculon N100" manufactured by Nippon Steel Chemical Co., Ltd.

The amount of the tackifier resin containing no active hydrogen in the above-mentioned base is limited to 50 to 100 parts by weight, preferably 60 to 80 parts by weight, per 100 parts by weight of the hydroxyl group-containing thermoplastic polyester urethane resin. It is. When the amount is less than 50 parts by weight, the adhesive composition over time of the obtained adhesive composition decreases. When the amount exceeds 100 parts by weight, the initial adhesiveness of the obtained adhesive composition is reduced.

As the imidazole compound used in the main agent of the first invention, R ¹ is H or a cyano lower alkyl group, and R ² is an alkyl group having 1 to 6 carbon atoms or a phenyl group in the general formula (1). Is used. However,
When the carbon number of R ² exceeds 6, the catalytic activity as a curing catalyst decreases, and the low-temperature curability deteriorates. Specifically, for example, compounds represented by the following general formulas (2) to (7) are exemplified.

[0022]

Embedded image

[0023]

Embedded image

[0024]

Embedded image

[0025]

Embedded image

[0026]

Embedded image

[0027]

Embedded image As a commercially available product of such an imidazole compound, for example, "Curesol 2MZ-CN" manufactured by Shikoku Chemicals is mentioned.

The amount of the imidazole compound in the above-mentioned base agent is determined by the amount of the hydroxyl group-containing thermoplastic polyester urethane resin 10
The amount is limited to 0.5 to 10 parts by weight, preferably 1 to 5 parts by weight, based on 0 parts by weight. When the compounding amount is less than 0.5 part by weight, the curing speed of the obtained adhesive composition,
In particular, when the curing speed is low at low temperatures, and when it exceeds 10 parts by weight, the pot life of the obtained adhesive composition is shortened, and the adhesive strength is also reduced. If necessary, a commonly used organometallic catalyst, amine catalyst or the like can be used together with the imidazole compound.

The main agent used in the second invention contains a hydroxyl group-containing thermoplastic polyester urethane resin, a tackifier resin containing no active hydrogen, an imidazole compound, and divalent tin salts.

The same components as those used in the first invention are used as the hydroxyl group-containing thermoplastic polyester urethane resin, the tackifier resin containing no active hydrogen, and the imidazole compound.

The divalent tin salt is represented by the following general formula (8)
It is represented by

[0032]

Embedded image

In the general formula (8), R ₄ and R ₅ represent a naphthenic acid residue represented by the general formula (9) or an octylic acid (2-ethylhexanoic acid) residue represented by the general formula (10). Represents a group.

[0034]

Embedded image

R ₄ and R _{5 in} the general formula (8) are not particularly limited, however, naphthenate,
It is preferred to select the octylate.

[0036]

Embedded image

In the main agent used in the second invention, the amount of the divalent tin salt is limited to 0.5 to 5 parts by weight, preferably 1 to 100 parts by weight of the hydroxyl group-containing thermoplastic polyester urethane resin. ３3 parts by weight. The amount is
If the amount is less than 0.5 part by weight, the effect of suppressing discoloration caused by light irradiation or high-temperature heating of the vinyl chloride resin film is small. If the amount is more than 5 parts by weight, the viscosity increase after mixing the curing agent is remarkably disturbing the coating operation. Cause.

The curing agent used in the adhesive composition of the present invention can be used without any particular limitation as long as it contains an isocyanate compound having two or more active isocyanate groups. Aromatic polyisocyanates such as diphenylmethane diisocyanate, xylylene diisocyanate, triphenylmethane triisocyanate; aliphatic polyisocyanates such as hexamethylene diisocyanate and 2,2,4-trimethylhexamethylene diisocyanate; hydrogenated tolylene diisocyanate isophorone diisocyanate;
Examples include alicyclic polyisocyanates such as hydrogenated diphenylmethane diisocyanate, and these may be used alone or in combination of two or more.

The curing agent is preferably used in a range of generally 1 to 200 parts by weight, based on 100 parts by weight of the hydroxyl group-containing thermoplastic polyester urethane resin in the main component.

In the adhesive composition of the present invention, the hydroxyl group-containing thermoplastic polyester urethane resin, the active hydrogen-free tackifying resin, and the imidazole compound represented by the general formula (1) (the second invention) Then
Further, a divalent tin salt is added thereto), and if necessary, other components are mixed in a predetermined amount and dissolved in an appropriate organic solvent to prepare a main agent.

As the solvent, at least one selected from the group consisting of ethyl acetate, methyl ethyl ketone, acetone, toluene, xylene, dichloromethane, 1,1,1-trichloromethane and the like is used. As the amount of the solvent,
The amount is preferably 50 to 5,000 parts by weight based on 100 parts by weight of the resin component (polyester urethane resin, tackifying resin, etc.).

The adhesive composition of the present invention may further contain an inorganic filler, a coloring agent, a stabilizer and the like, if necessary.

The adhesive composition of the present invention is excellent in initial adhesiveness, normal adhesive strength, heat resistance, water resistance and the like, and is widely used for bonding various materials such as plastic, metal and wood. In particular, it is suitably used for producing a decorative sheet covering material having a curved surface or an uneven surface requiring strong initial adhesiveness.

The adhesive composition of the present invention is suitably used for producing a decorative sheet covering material having a curved surface or an uneven surface. As decorative sheets, vinyl chloride resin, vinylidene chloride resin, polyethylene resin, polypropylene resin, polystyrene resin, ABS resin, polyamide resin, polyester resin, polyurethane resin, polyvinyl alcohol resin, ethylene-vinyl acetate copolymer resin, chlorinated polypropylene Sheets of plain or letters or patterns made of synthetic resin such as resin, sheet sheets of wood, sheet sheets impregnated with synthetic resin, metal foil such as aluminum foil, paper,
Cloth or the like is used.

As the adherend, vinyl chloride resin, vinylidene chloride resin, polyethylene resin, polypropylene resin, polystyrene resin, ABS resin, polyamide resin,
Synthetic resins such as polyester resin, polyurethane resin, polyvinyl alcohol resin, ethylene-vinyl acetate copolymer resin, and chlorinated polypropylene resin; natural wood, plywood,
Wood such as particle board, hard fiber board, semi-hard fiber board, glued wood; aluminum, iron,
A molded article made of a metal such as stainless steel and having an irregular cross section may be used.

As a method for producing a decorative sheet covering material using the adhesive composition of the present invention, first, a decorative sheet is supplied, the adhesive composition of the present invention is applied to the back of the decorative sheet, and then hot air is applied. And dried. The application of the adhesive is performed by a knife coater, a roll coater, a curtain flow coater, a spray, or the like.
It is applied so as to have a thickness of 500 μm, preferably 5 to 300 μm. The drying temperature in the drying step is generally room temperature to 10
0 ° C is preferable, and more preferably 40 to 60 ° C.
The drying time is preferably from 1 second to 30 minutes, more preferably from 5 seconds to 1 minute.

Next, the decorative sheet is coated along the surface of the adherend and pressed by a roll or the like, or pressed by a rubber plate of a vacuum forming machine to obtain a decorative sheet covering material. The pressure during crimping is generally 0.1
It is performed instantaneously at about 10 kg / cm. The combination of the decorative sheet and the adherend is not particularly limited, but particularly preferable combinations include, for example, a synthetic resin sheet and wood, a synthetic resin sheet and metal, a synthetic resin sheet and synthetic resin, a laminated sheet and wood, Is mentioned.

[0048]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to examples according to the present invention and comparative examples to which the present invention is applied.

(Examples 1 to 5, Comparative Examples 1 to 4) 1) Production of Adhesive Composition (1) Preparation of Main Agent Dainippon Ink as a hydroxyl group-containing thermoplastic polyester urethane resin having the compounding amount shown in Table 1 "Pandex T-5201" (weight average molecular weight 100,000 to 150,000) manufactured by Kagaku or "Pandex T-5202" manufactured by Dainippon Ink and Chemicals, Inc.
(Weight average molecular weight of 200,000 to 220,000), Nippon Steel Chemical Co., Ltd. "Escron N"
100 "(coumarone-indene-styrene copolymer),
In addition, "Cyazole 2MZ-CN" manufactured by Shikoku Chemicals Ltd. as an imidazole compound was dissolved in dichloromethane to prepare a main agent.

(2) Preparation of curing agent As an isocyanate compound having two or more active isocyanate groups, diphenylmethane diisocyanate in an amount shown in Table 1 was blended to obtain a curing agent.

(3) Production of Adhesive Composition The above main agent and the above curing agent were mixed in the mixing ratio shown in Table 1 to obtain an adhesive composition.

2) Preparation of decorative sheet coating material Profile laminator ("PL-30" manufactured by Marunaka Shoji Co., Ltd.)
0 "), a vinyl chloride resin sheet having a thickness of 170 μm was supplied at a speed of 15 m / min, and the adhesive composition obtained above was applied on one surface thereof with a knife coater to a thickness of 100 μm. Is passed through a hot air drying oven and dried, and while covering it from the surface of the adherend consisting of semi-rigid fiberboard with irregular cross-section to both edges of the back surface, press it with a pressure roller to cover the decorative sheet Materials were made.

The above-mentioned adhesive composition was prepared by mixing a predetermined amount of a main agent and a curing agent shown in Table 1 and then mixing at 5 ° C., 20 ° C. and 3 ° C.
After leaving at 0 ° C. for 0, 4, and 8 hours, respectively, it was applied to a vinyl chloride resin sheet and the adherend was pressed. The adherend (semi-rigid fiber board) has a length of 2 m, a width of 100 mm, and a thickness of 20 mm, and has a surface having a depth and width of about 5 mm and a corner R of 2 mm. Groove 70m
They are provided in the length direction at m intervals.

The profile laminator includes a supply roll for continuously feeding a decorative sheet, a knife coater for applying an adhesive to the decorative sheet, a hot air dryer for drying the applied adhesive, and a fixed length. Material supply device for supplying the material to be adhered, a pressure roll for covering the decorative sheet along the curved surface or uneven surface of the material while covering the decorative sheet with the material, and applying the decorative sheet. A cutter having a cutter for cutting according to the length of the material was used.

With respect to the adhesive composition and the decorative sheet covering material obtained in the above Examples and Comparative Examples, the following items (I)
And (II) were measured, and the measurement results are shown in Table 2.

(I) Normal Peeling Test The flat part of the decorative sheet covering material immediately after production was 100 m in length.
The test piece was cut into a size of mx 25 mm in width, and one end of the decorative sheet was peeled off in advance. After the test piece immediately after the preparation was cured at 5 ° C., 20 ° C., and 30 ° C. for 2 hours, one end of the adherend and the decorative sheet were fixed to a chuck, and the temperature was 20 ° C. and the humidity was 60% RH. A 180-degree peeling test was performed at a pulling speed of 200 mm / min using an autograph in the atmosphere described above, and the measurement results (peeling strength) are shown in Table 2.

(II) Pot life After mixing the main agent and the curing agent, 150 g was put into a 200 ml sealable glass bottle, sealed, and sealed at 5 ° C., 20 ° C., 30 ° C.
The viscosities before and after standing for 8 hours in an atmosphere of ° C. were measured using a BM type viscometer, and the measurement results are shown in Table 2.

[0058]

[Table 1]

[0059]

[Table 2]

(Examples 6 to 10, Comparative Examples 5 to 10) 1) Production of adhesive composition (1) Preparation of main agent A large amount of a hydroxyl group-containing thermoplastic polyester-based urethane resin having the compounding amount shown in Tables 3 and 4 "Pandex T-5201" (weight average molecular weight 100,000-1
50,000), "Esculon N100" (coumarone-indene-styrene copolymer) manufactured by Nippon Steel Chemical Co., Ltd. as a tackifying resin containing no active hydrogen, "Cureazole 2MZ-CN" manufactured by Shikoku Chemicals as imidazole compound, and octylic acid Tin or tin naphthenate was dissolved in dichloromethane to prepare a main ingredient.

(2) Preparation of curing agent As an isocyanate compound having two or more active isocyanate groups, diphenylmethane diisocyanate was added in an amount shown in Tables 3 and 4 to obtain a curing agent.

(3) Production of Adhesive Composition The above main agent and the above curing agent were mixed in the mixing ratios shown in Tables 3 and 4 to obtain an adhesive composition.

[0063]

[Table 3]

[0064]

[Table 4]

2) Preparation of a decorative sheet covering material A decorative sheet covering material was prepared in the same manner as in Example 1 using the adhesive compositions obtained in Examples 6 to 10 and Comparative Examples 5 to 10. did.

The adhesive composition and decorative sheet covering material obtained in Examples 6 to 10 and Comparative Examples 5 to 10 were subjected to the same normal peel test and measurement of pot life as in Example 1, and The following (III) and (IV) were evaluated, and the measurement results and evaluation results are shown in Tables 5 and 6.

(III) Discoloration by Light Irradiation The above decorative sheet covering material was left at 20 ° C. for 7 days, cut into test pieces of 100 mm width × 200 mm length × 20 mm thickness, and “Atlas CXW” manufactured by Toyo Seiki Co., Ltd. (With a Yurex D folder) "for 1000 hours, taken out and visually observed, and the degree of discoloration was determined according to the following evaluation criteria. [Evaluation Criteria] 5: No discoloration compared to before exposure 4: Discoloration is difficult to recognize unless care is taken 3: Discoloration is recognized but the degree is small 2: Discoloration is clearly recognized, and deep coloration proceeds Yes 1: Black

(IV) Discoloration by High Temperature Heating The decorative sheet covering material was left in an atmosphere of 180 ° C., and the degree of discoloration was visually observed every 15 minutes, and the degree of discoloration was evaluated according to the same evaluation criteria as in (III). Judged.

[0069]

[Table 5]

[0070]

[Table 6]

Since the adhesive composition of the first invention has a longer pot life and a higher curing speed after bonding than the conventional one by adopting the above constitution, the adhesive composition after bonding Quickly develops, and the workability and adhesiveness can be improved.

The adhesive composition of the second invention has a longer pot life and a higher curing speed after bonding than the conventional adhesive composition by adopting the above constitution. The adhesive strength of the film is fast, workability and adhesiveness can be improved, and even if the adherend is a vinyl chloride resin film, There is no discoloration.

Therefore, the adhesive composition of the present invention can be suitably used for producing a decorative sheet covering material.

Claims (2)

[Claims] 1. Hydroxy group-containing thermoplastic polyester urethane resin 100 parts by weight, active hydrogen-free tackifying resin 50 to 100 parts by weight, and an imidazole compound 0.5 to 10 represented by the following general formula (1) A base agent containing parts by weight; (Wherein R ¹ is a hydrocarbon group having a CN group or H, R ²
Is a hydrocarbon group having 1 to 6 carbon atoms, and R ³ is CH ₃ or H. An adhesive composition comprising: a curing agent containing an isocyanate compound having two or more active isocyanate groups. 2. 100 parts by weight of a hydroxyl group-containing thermoplastic polyester urethane resin, 50 to 100 parts by weight of a tackifier resin containing no active hydrogen, and 0.5 to 10 parts by weight of an imidazole compound represented by the following general formula (1). And a main agent containing 0.5 to 5 parts by weight of a divalent tin salt; (Wherein R ¹ is a hydrocarbon group having a CN group or H, R ²
Is a hydrocarbon group having 1 to 6 carbon atoms, and R ³ is CH ₃ or H. An adhesive composition comprising: a curing agent containing an isocyanate compound having two or more active isocyanate groups.