JPH1121534A - Adhesive composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an adhesive composition especially useful for polyolefin films which are not deteriorated under the influence of ultraviolet rays and can keep film bonding strength because polyolefin film laminates used outdoors markedly suffer ultraviolet deterioration in the strength of joints and can be hardly used in long-time outdoor applications. SOLUTION: There is provided an adhesive composition comprising an adhesive base and a curing agent, wherein the adhesive base is a polyester having 0.05-0.9 wt.%, per 100 pts.wt. resin component of the base, terminal active hydroxyl groups, at least 70 mol.% of the acid component of the starting polyester of the polyester are isophthalic residues, at least 70 mol.% of the alcohol component are a linear alkyl diol, and the curing agent is a polyisocyanate containing 15-35 wt.%, per 100 pts.wt. resin component of the curing agent, of terminal active isocyanate groups. When this is used as an adhesive of a polyolefin film laminate, the laminate has reduced decrease in bonding strength when it is subjected to an ultraviolet deterioration test.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an adhesive composition capable of maintaining the strength of an adhesive joint for a long period without being affected by ultraviolet deterioration of an olefin film or sheet.

[0002]

2. Description of the Related Art Hitherto, polyolefin-based composite films and sheets have been used in various fields such as industrial and agricultural fields as extremely useful materials. In addition, the polyolefin-based composite film and sheet are attracting attention as a substitute for a polyvinyl chloride film from the viewpoint of environmental protection,
For example, Japanese Patent Application Laid-Open Nos. Hei 6-79830 and Hei 6-198831 disclose that it is effective for embossing and other decorative sheet materials. However, in applications exposed to sunlight such as cosmetics and agricultural use, even if the strength of the adhesive joint is subjected to a necessary treatment such as corona discharge treatment, the film or sheet may be deteriorated by ultraviolet light. Has a serious drawback that it significantly decreases as the process proceeds. On the other hand, as a deterioration-resistant adhesive composition containing a polyester polyol and an isocyanate compound,
Polyester polyol (A) having a molecular weight of 2,000 to 100,000, carboxy-containing acrylonitrile-butadiene copolymer (B), and polyfunctional isocyanate (C)
An adhesive composition comprising
259985). Further, a mixture comprising a polyester polyurethane polyol and a polyester resin having a carboxyl group at a molecular terminal, an adhesive composition containing orthophosphoric acid and an organic isocyanate compound, and the like have been proposed (JP-A-8-120250, etc.). These are intended for the purpose of improving the initial adhesiveness, water resistance and plasticity resistance when laminating a polyester film and a soft vinyl chloride resin film, or to strengthen a plastic film or a plurality of plastic films or metal foils and plastic films. It is for food packaging materials that are composite-laminated with bonding strength, and does not maintain or suppress the adhesive strength that decreases with the progress of ultraviolet degradation. Therefore, particularly with respect to adhesion of the polyolefin composite film and sheet, it has been desired to develop an adhesive composition which is not affected by ultraviolet deterioration even under conditions of exposure to sunlight, such as for cosmetic use and agricultural use.

[0003]

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide an adhesive composition which maintains the strength of an adhesive joint for a long period of time without being affected by ultraviolet deterioration of an olefin film or sheet. To provide.

[0004]

Under these circumstances, the present inventors have conducted intensive studies and as a result, have used polyesters having a specific structure as an adhesive main agent and polyisocyanates having a specific structure as a curing agent. The present inventors have found that an adhesive composition can maintain the strength of an adhesive joint for a long period without being affected by ultraviolet deterioration of an olefin-based film or sheet, and have completed the present invention. That is, the present invention comprises an adhesive main agent and a curing agent, wherein the adhesive main agent has an active hydroxyl group at the terminal and a resin component 1 of the main agent.
Polyesters having 0.05 to 0.9% by weight per 100 parts by weight, and 70% by mole or more of an acid component of a raw material polyester of the polyesters is an isophthalic acid residue;
70% by mole or more of the alcohol component is a linear alkyl diol, and the curing agent has an isocyanate group having an active terminal at 15 to 100 parts by weight per 100 parts by weight of the resin component of the curing agent.
An adhesive composition comprising 35% by weight of a polyisocyanate.

[0005]

BEST MODE FOR CARRYING OUT THE INVENTION The polyester which is the main component of the adhesive of the present invention has an active hydroxyl group at the terminal and a resin component 1 of the main component.
When the hydroxyl group at the terminal is less than 0.05%, it is difficult to obtain the required adhesive strength. This is not preferable because the strength decreases after the ultraviolet ray deterioration test.

[0006] The polyesters are polyesters or derivatives thereof, and specific examples thereof include polyester polyols and polyester polyurethane polyols. Of these, polyester polyols are preferred. The polyester polyurethane polyol can be obtained by urethanizing a polyester polyol using a conventionally known diisocyanate compound and a chain extender.

The polyesters used in the present invention are obtained by polycondensing a polybasic acid or its ester compound and a polyhydric alcohol at a temperature of 200 to 250 ° C. in a reaction vessel. Although not particularly limited, 1,000 to 100,000, preferably 5,000 to 50,0
00 is used.

The polybasic acid and its ester compound are not particularly limited, but specific examples include isophthalic acid,
Aromatic polybasic acids such as phthalic acid and terephthalic acid; aliphatic polybasic acids such as succinic acid, adipic acid, suberic acid, azelaic acid and sebacic acid; unsaturated fatty acids such as maleic acid, fumaric acid, itaconic acid and the like Acid anhydrides and ester compounds thereof, of which dimethyl isophthalate,
Dimethyl terephthalate is preferred. These can be used alone or in combination of two or more.

Specific examples of polyhydric alcohols include ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, dipropylene glycol, 1,3-butanediol, 1,4-butanediol, and 1,5-butanediol.
Pentanediol, neopentyl glycol, 3-methyl
1,5-pentanediol, 1,6-hexanediol, cyclohexanediol, cyclohexanedimethanol, bisphenol A, etc., among which alkyl such as ethylene glycol, 1,4-butanediol, 1,6-hexanediol, etc. Diols are preferred. These can be used alone or in combination of two or more.

In the present invention, 70% by mole or more, preferably 75% by mole or more, more preferably 80% by mole or more of the acid component of the raw material polyester of the above-mentioned polyesters is 70% by mole of the isophthalic acid residue and the alcohol component. %
Or more, preferably 75 mol% or more, more preferably 80 mol% or more.
At least mol% is a linear alkyl diol. 70% of isophthalic acid residue in the acid component of the polyester
If the ratio is less than 70%, and if the proportion of the linear alkyl diol in the alcohol component is less than 70%, it is not preferable because the adhesive strength to the olefin film interface is significantly reduced in a short time in an ultraviolet irradiation test.

The polyisocyanate as the curing agent of the present invention has an active isocyanate group at the terminal in an amount of 15 to 35% by weight per 100 parts by weight of the resin component of the curing agent. If it is less than 35%, the initial strength is insufficient, and if it exceeds 35% by weight, the strength with time decreases significantly, which is not preferable. As the polyisocyanate, at least two, preferably 3
Polyisocyanate compounds having more than one isocyanate group can be used. Specifically, polyisocyanates such as hexamethylene diisocyanate, isophorone diisocyanate, tolylene diisocyanate, xylylene diisocyanate, water-added xylene diisocyanate, 4,4'-diphenylmethane isocyanate, 4,4'-dicyclohexylmethane diisocyanate; Modified products such as modified burette, modified allophanate, modified isocyanurate, and modified carbodiimide; adducts obtained by reacting the polyisocyanate with polyhydric alcohol; and the like.

In the present invention, the compounding ratio of the adhesive main agent and the curing agent is 1.5 to 4.0 as the ratio of NCO / OH of the terminal group.
The range may be set to 5. When the NCO / OH ratio is less than 1.5, it is difficult to obtain the necessary adhesive strength, and the strength is significantly reduced by an ultraviolet ray deterioration test.
If it exceeds, the adhesive layer tends to be a defect-prone adhesive layer, and sufficient strength cannot be obtained from the beginning, which is not preferable.

The adhesive composition of the present invention comprises 2- (3,5-di-t-amyl-2-hydroxyphenyl) benzotriazole, 2- (5-methyl) Benzotriazole ultraviolet absorbers such as -2-hydroxyphenyl) benzotriazole or bis (2,2 ', 6,6'-tetramethyl-4-piperidyl) sebacate, tetrakis (2,
(2 ', 6,6'-tetramethyl-4-piperidyl) 1,2,3,4-butane tetracarboxylate It is also preferable because it can be performed. Further, the benzotriazole ultraviolet absorber and the hindered amine light stabilizer can be used alone or in combination,
Preferably, they are used in combination. The blending ratio of the benzotriazole-based ultraviolet absorber is 0.1 to 2.0 parts by weight with respect to 100 parts by weight of the resin component of the adhesive base agent, and the blending ratio of the hindered amine-based light stabilizer is Is preferably 0.1 to 2.0 parts by weight. Also,
The adhesive composition is used as an adhesive composition compounding solution by diluting the above components in an organic solvent such as ethyl acetate at an appropriate magnification.

The adhesive composition of the present invention is applied to the surface of a cosmetic base sheet such as a polyolefin-based film, polyvinyl chloride-based film, polyester-based film, acrylic-based film, etc., and a polyolefin-based film is applied thereon. , Polyester-based film, used for bonding when sequentially laminating a surface layer such as an acrylic-based film, particularly,
The effect on the adhesion of the polyolefin film is remarkable. To make such a multilayer composite film, a commonly used method, for example, an adhesive is applied to one surface of one of the substrates by a dry laminator, and after the solvent is volatilized, the other laminated base is laminated, What is necessary is just to harden under normal temperature or heating. The amount of the adhesive applied to the surface of the laminate substrate is not particularly limited, but is 1 to 10 g /
m ² .

[0015]

Next, the present invention will be described in more detail with reference to examples, but this is merely an example and does not limit the present invention.

Example 1 776 g of dimethyl isophthalate, dimethyl sebacate 2
30 g, 382 g of 1,6-hexanediol, 146 g of 1,4-butanediol, 33.5 g of ethylene glycol, and 0.2 g of zinc acetate dihydrate as a transesterification catalyst.
The mixture was charged in a 4-liter four-neck flask, heated to 160 to 200 ° C. while stirring under a nitrogen stream, and transesterified while distilling methanol. When distillation of methanol stopped, 0.3 g of antimony trioxide was added, and 25
The temperature was raised to 0 ° C., and polycondensation was performed under reduced pressure of 10 mmHg to obtain a polyester having a hydroxyl group content of 0.20% by weight. The polyester contained 80 mol% of the isophthalic acid residue in the acid component of the raw material polyester, and 100 mol% of the linear alkyl diol in the alcohol component. This polyester was dissolved in toluene to form a solution having a nonvolatile content of 60%, and 0.5 parts by weight of 2- (3,5-di-t-t) was added to 100 parts by weight of the resin component.
-Amyl-2-hydroxyphenyl) benzotriazole and 0.5 parts by weight of bis (2,2 ', 6,6'-tetramethyl-4-
Addition of piperidyl) sebacate and adhesive base material (1)
I got Next, 9 parts by weight of an isocyanurate-modified hexamethylene diisocyanate (NCO content: 21.2%) was added as a curing agent to 100 parts by weight of the adhesive base material-containing material (1), and the nonvolatile content was 25% with ethyl acetate. To obtain an adhesive composition-mixed liquid. Next, the adhesive strength before and after the ultraviolet ray deterioration test of the adhesive composition mixture liquid was measured by the following evaluation method. Table 1 shows the results. In the table, the symbol A indicates the peeling between the adhesive and the Esporal A, and the symbol B indicates the Esporal A film breakage.

(Evaluation method) Each adhesive composition compounding liquid (25
%) With 25 lines of 120μ gravure roll and 25μPET
5g / m on the treated surface of film # 5102 (Toyobo Co., Ltd.)
^2- dry coating, drying at 70 ° C. for 3 minutes, and then using a laminating roll at 40 ° C. to obtain 50 μs of ESPOIR AP
M-1 (special olefin film manufactured by Mitsui Toatsu Chemicals Co., Ltd.) was bonded to the treated surface and aged at 40 ° C. for 1 week to prepare a test sample, which was subjected to an ultraviolet deterioration test (accelerated test). The ultraviolet deterioration test was performed using a carbon arc light source fade meter (black panel temperature 63 ° C) and PET.
Irradiation was performed for 1000 hours from the film surface. Further, the adhesive strength before and after the ultraviolet ray deterioration test was measured by a T-type peeling method specified in the peeling adhesive strength test method of JIS K-6854 adhesive.

Example 2 97 g of dimethyl terephthalate, dimethyl isophthalate 7
76 g, 115 g of dimethyl sebacate, 407 g of 1,6-hexanediol, 120 g of neopentyl glycol, 71.3 g of ethylene glycol and 0.2 g of zinc acetate dihydrate as a transesterification catalyst were charged into a two-liter four-necked flask, and the nitrogen gas flow was continued. 160-200 ° C while stirring under
And transesterified while distilling off methanol. When distillation of methanol stopped, 0.3 g of antimony trioxide was added, the temperature was raised to 250 ° C., and 10 mm
Polycondensation was performed under reduced pressure of Hg to obtain a polyester having a hydroxyl group content of 0.34% by weight. The polyester contained 80 mol% of isophthalic acid residues in the acid component of the raw material polyester and 80 mol% of the linear alkyl diol in the alcohol component. This polyester is dissolved in toluene to form a solution having a nonvolatile content of 60%, and 0.5 parts by weight of 2- (5-methyl-2-hydroxyphenyl) benzotriazole and 0.5 parts by weight are added to 100 parts by weight of the resin component. Part of the screw (2,2 ′,
(6,6'-Tetramethyl-4-piperidyl) sebacate was added to obtain an adhesive base material-containing substance (2). Next, an isocyanurate-modified hexamethylene diisocyanate (NC) was used as a curing agent in 100 parts by weight of the adhesive base material-containing material (2).
(O content: 21.2%), 9 parts by weight, and diluted with ethyl acetate to a nonvolatile content of 25% to obtain an adhesive composition formulation.

Comparative Example 1 291 g of dimethyl terephthalate, 388 g of dimethyl isophthalate, 345 g of dimethyl sebacate, 130 g of 1,6-hexanediol, 286 g of neopentyl glycol,
102 g of ethylene glycol and 0.2 g of zinc acetate dihydrate as a transesterification catalyst were charged into a 2-liter four-necked flask, and stirred at 160 to 200 ° C. under a nitrogen stream.
And the transesterification reaction was performed while distilling off methanol. When distillation of methanol stopped, 0.3 g of antimony trioxide was added, and the temperature was raised to 250 ° C.
Polycondensation was performed under reduced pressure of mmHg to obtain a polyester having a hydroxyl group content of 0.25% by weight. The polyester has an isophthalic acid residue content of 40 mol% in the acid component of the raw polyester,
In the alcohol component, the linear alkyl diol was 50 mol%. This polyester was dissolved in toluene to form a solution having a nonvolatile content of 60%, thereby obtaining an adhesive base material-containing substance (3). Next, to 100 parts by weight of the adhesive base material-containing material (3),
9 parts by weight of a modified isocyanurate of hexamethylene diisocyanate (NCO content: 21.2%) was added as a curing agent, and the mixture was diluted with ethyl acetate to a nonvolatile content of 25% to obtain a liquid composition containing an adhesive composition.

Comparative Example 2 0.5 parts by weight of 2- (5-methyl-2-hydroxyphenyl) benzotriazole and 0.5 parts by weight were added to 100 parts by weight of the resin component of the adhesive base material-containing material (3). Screw (2,2 ′,
6,6'-Tetramethyl-4-piperidyl) sebacate was added to obtain an adhesive base material-containing substance (4). Next, isocyanurate-modified hexamethylene diisocyanate (NC) was used as a curing agent in 100 parts by weight of the adhesive base material-containing material (4).
(O content: 21.2%), 9 parts by weight, and diluted with ethyl acetate to a nonvolatile content of 25% to obtain an adhesive composition formulation.

Comparative Example 3 679 g of dimethyl isophthalate, dimethyl adipate 2
61 g, 445 g of diethylene glycol, 65.1 g of ethylene glycol, and 0.2 g of zinc acetate dihydrate as a transesterification catalyst were charged into a two-liter four-necked flask, heated to 160 to 200 ° C. while stirring under a nitrogen stream, and methanol was distilled off. The transesterification reaction was performed while the mixture was being discharged. When the distillation of methanol stopped, 0.3 g of antimony trioxide was added, the temperature was raised to 250 ° C., and polycondensation was performed under reduced pressure of 10 mmHg to obtain a polyester having a hydroxyl group content of 0.17% by weight. The polyester contained 70 mol% of isophthalic acid residues in the acid component of the raw material polyester, and 20 mol% of the linear alkyl diol in the alcohol component. This polyester was dissolved in toluene to form a solution having a nonvolatile content of 60%.
0.5 parts by weight of 2- (5-methyl-2-hydroxyphenyl)
Benzotriazole was added to obtain an adhesive main agent-containing substance (5). Next, to 100 parts by weight of the adhesive base material-containing material (5),
9 parts by weight of a modified isocyanurate of hexamethylene diisocyanate (NCO content: 21.2%) was added as a curing agent, and the mixture was diluted with ethyl acetate to a nonvolatile content of 25% to obtain a liquid composition containing an adhesive composition.

The measurement of the adhesive strength before and after the ultraviolet ray deterioration test of the adhesive composition mixture liquids of Example 2 and Comparative Examples 1 to 3 was performed in the same manner as in Example 1. Table 1 shows the results.

[0023]

[Table 1]

[0024]

According to the present invention, an active hydroxyl group at the terminal is used as an adhesive main agent in an amount of 0.1 to 100 parts by weight of a resin component of the main agent.
A polyester having from 0.05 to 0.9% by weight, in which 70% by mole or more of the acid component of the raw polyester is an isophthalic acid residue and 70% by mole or more of the alcohol component is a linear alkyl diol, is cured. Since the adhesive composition used was a polyisocyanate having 15 to 35% by weight per 100 parts by weight of the resin component of the curing agent, the composition was exposed to sunlight for industrial and agricultural uses. In particular, when used as an adhesive for a polyolefin-based film laminate, it is possible to prevent a decrease in adhesive strength due to ultraviolet deterioration of the polyolefin-based film, and to obtain a stable adhesive strength over a long period of time.

Claims (3)

[Claims] 1. An adhesive comprising a main agent and a curing agent,
The adhesive main component is a polyester having an active hydroxyl group at a terminal in an amount of 0.05 to 0.9% by weight per 100 parts by weight of the resin component of the main component, and 70 mol of an acid component of a raw material polyester of the polyester. % Or more is an isophthalic acid residue, 70% or more of an alcohol component is a linear alkyl diol, and the curing agent has an active isocyanate group at a terminal in an amount of 15 to 35 parts per 100 parts by weight of the resin component of the curing agent. An adhesive composition which is a polyisocyanate having a percentage by weight. 2. The adhesive composition according to claim 1, wherein the mixing ratio of the adhesive main agent and the curing agent is in the range of 1.5 to 4.5 in terms of the terminal group NCO / OH ratio. 3. A benzotriazole-based ultraviolet absorber or 0.1-2.0 parts by weight of a hindered amine-based light, based on 100 parts by weight of the resin component of the adhesive base agent. 3. The adhesive composition according to claim 1, further comprising a stabilizer.