JP2003003145A - Solventless adhesive and method of laminating - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a polyester type solventless adhesive capable of producing a laminated product comprising a plastic sheet or film, metallized plastic film or a metal foil by a solventless laminating method. SOLUTION: This solventless adhesive comprising a polyesterpolyol as a principal ingredient which is a copolymer type polyesterpolyol including 0.5 to 3.0 wt.% of hydroxy group, and a polyisocyanate as a hardening agent having 10 to 30 wt.% of the isocyanate group content, and the laminating method laminating the film or sheet like base material uses the solventless adhesive.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a solventless adhesive suitable for producing a laminated product having excellent durability and a laminating method using the same.

[0002]

2. Description of the Related Art As packaging materials and industrial materials, various plastic films and sheets, vapor-deposited plastic films and base materials such as metal foils are compounded using an adhesive,
Laminated products that take advantage of the characteristics of each material are often used. As a method for manufacturing the above laminated product using an adhesive, there are a dry laminating method using a solution type adhesive and a solventless laminating method using a solventless adhesive.

In the dry laminating method using a solvent-type adhesive, one substrate or a two-component solvent-type adhesive is applied to one substrate by gravure coating or the like, the solvent is evaporated, and then the other substrate is heated. Laminated products are manufactured by crimping with. On the other hand, in the solventless laminating method using a solventless adhesive, a solventless one-component or two-component adhesive is applied to one substrate by a roller feed method, and the other substrate is heated with a heating roll. A laminated product is manufactured by pressure bonding.

[0004]

Since the dry laminating method requires a drying furnace for solvent evaporation, the equipment cost is high, and in addition to quality problems due to residual solvent, air pollution and work environment in recent years are also a problem. The adoption of the solventless laminating method tends to increase because it is necessary to deal with it. With that,
Solventless adhesives are also under study. For example, ether-based polyurethane prepolymer one-component and two-component solventless adhesives have been developed for adhering plastic films to each other.

However, with this solventless adhesive, sufficient adhesive strength cannot be obtained in a laminated product having a constitution including a plastic film or sheet, a vapor-deposited plastic film or a metal foil, and a polyester / polyisocyanate type or polyester polyurethane is not obtained. / It was necessary to use a dry laminating method using a polyisocyanate-based solvent-type two-component curing type adhesive. Therefore, it was studied to remove the solvent from a normal solvent-type polyester / polyisocyanate-based two-component curing type adhesive to remove the solvent, but there was a problem that the viscosity became high and lamination was difficult. Further, when the molecular weight of the polyester is lowered to a viscosity at which it can be laminated, there is a problem that the initial tackiness is lowered and the appearance is poor such as tunneling.

Therefore, an object of the present invention is to solve the above problems and to manufacture a laminated product having a constitution including a plastic sheet or film, a vapor-deposited plastic film or a metal foil by a solventless laminating method. It is to provide a solventless adhesive.

[0007]

As a result of intensive studies to solve the above-mentioned problems, the inventors of the present invention have found that a solventless adhesive in which a main component is a copolymer type polyester polyol and a curing agent is a polyisocyanate is used. It was found that a laminated product having a constitution including a plastic sheet or film having a practically sufficient adhesive strength, a vapor-deposited plastic film or a metal foil can be obtained by use, and the present invention has been completed.

That is, the present invention is a solventless adhesive in which the main component is a polyester polyol and the curing agent is a polyisocyanate, and the polyester polyol has a hydroxyl group content of 0.5 to 6.0% by weight. The polyisocyanate has an isocyanate group content of 10 to 30% by weight, and when the solventless adhesive and the sheet-shaped or film-shaped substrate are laminated, the solventless adhesive is used. It is a laminating method characterized by the above.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will now be described in more detail. First, the copolymer type polyester polyol used in the present invention will be described. The copolymer type polyester polyol is a polyester polyol which is liquid or solid at room temperature and is obtained by copolymerizing (condensation polymerization) a plurality of dicarboxylic acid components and a plurality of diol components.

As the dicarboxylic acid component, aromatic, alicyclic and aliphatic dicarboxylic acids conventionally used in the production of polyester are used, but these are not limited. As the aromatic dicarboxylic acid,
For example, isophthalic acid, orthophthalic acid, terephthalic acid, 2,6-naphthalenedicarboxylic acid, para-phenylenedicarboxylic acid and the like and esters of these lower alcohols such as methyl alcohol may be used as alicyclic dicarboxylic acids such as 1,4 -Cyclohexanedicarboxylic acid and the like and esters of these lower alcohols such as methyl alcohol. Further, as the aliphatic dicarboxylic acid, for example, the general formula HOOC (CH ₂ ) _n COOH
Examples thereof include succinic acid, glutaric acid, adipic acid, suberic acid, azelaic acid, sebacic acid, dodecanedioic acid, etc. represented by (n is an integer of about 1 to 10) and esters of these lower alcohols such as methyl alcohol. .

The proportion of the above-mentioned dicarboxylic acid used is such that the aromatic dicarboxylic acid and / or the alicyclic dicarboxylic acid (a) are used.
To aliphatic dicarboxylic acid (b) molar ratio [(b) /
(B)] is preferably 5/95 to 95/5,
The ratio is more preferably 30/70 to 90/10. If the above molar ratio is less than 5/95, there is a problem in adhesion performance, and if it exceeds 95/5, there is a problem in that it becomes hard and poor in flexibility.

As the diol component, those conventionally used in the production of polyester can be used and are not particularly limited. Examples of the aliphatic diol include ethylene glycol, propylene glycol, 1,3-butanediol, 1,4-butanediol, 1,5-pentanediol, neopentyl glycol, 3-methyl-1,5.
Aliphatic diols having 2 to 8 carbon atoms such as -pentanediol and 1,6-hexanediol, and examples of alicyclic diols include 1,4-cyclohexanediol and
1,4-cyclohexanedimethanol and the like include alkylenediols such as diethylene glycol and
Examples include triethylene glycol and dipropylene glycol.

The use ratio of the above diol component is such that the molar ratio [(ha) / (d)] of the aliphatic diol and / or alicyclic diol (ha) and the alkylene diol (d) is 5.
A ratio of / 95 to 95/5 is preferable, and a ratio of 50/50 to 90/10 is more preferable. If the above molar ratio is less than 5/95, there is a problem in heat resistance.
If it exceeds, there is a problem that wettability and flexibility become poor.

The hydroxyl group content of the copolymer type polyester polyol is 0.5 to 6.0% by weight, preferably 1.0 to 3.5% by weight. When the hydroxyl group content is less than 0.5% by weight, the crosslink density of the adhesive is low, it is difficult to obtain sufficient heat resistance, and the coating workability at high viscosity is poor.
If it exceeds 5% by weight, the initial tackiness of the adhesive is remarkably lowered, which hinders the laminating operation and requires a long time for aging, which is not practical.

The copolymer type polyester polyol used in the present invention can be produced by a conventionally known method for producing polyester, and the production method is not particularly limited.
That is, the dicarboxylic acid component and the diol component are added in an amount of 200-25
Obtained by polycondensation under reduced pressure at a temperature of 0 ° C. At that time, if necessary, a part of the dicarboxylic acid can be replaced with a tricarboxylic or higher polycarboxylic acid such as trimellitic acid or pyromellitic acid, as long as the gist of the present invention is not impaired. Similarly, a part of the diol can be replaced with a polyol having a valency of 3 or more such as trimethylolpropane and pentaerythret. The copolymerizable polyester polyol obtained above is liquid or solid at room temperature,
A preferable weight average molecular weight (measured by GPC, converted to standard polystyrene) is 1,000 to 3,500.

Next, the polyisocyanate as the curing agent used in the present invention will be described. The polyisocyanate used in the present invention has an isocyanate group content of 10 to 30% by weight, preferably 15 to 25% by weight. If the isocyanate group content is less than 10% by weight, the crosslink density after curing the adhesive is too low, and if it exceeds 30% by weight, the raw material diisocyanate in the polyisocyanate may remain at 1% by weight or more. Occasionally, there is a problem of environmental pollution due to volatilization of the raw material diisocyanate. It is necessary that 1% or more of the raw material diisocyanate does not remain in the polyisocyanate.

The polyisocyanate used in the present invention is
Any diisocyanate conventionally used in the production of polyurethane can be used and is not particularly limited. Examples of the aliphatic polyisocyanate include hexamethylene diisocyanate (HDI) and its condensates.
Examples of the alicyclic polyisocyanate include isophorone diisocyanate (IPDI) and its condensates, and examples of the aromatic polyisocyanate include toluene diisocyanate (2,4-TDI, 2,6-TD).
I and mixtures thereof, and condensates such as their dimers and trimers are preferred. Among the above polyisocyanates, aliphatic polyisocyanates, alicyclic polyisocyanates and their condensates are more preferable in terms of heat resistance and light discoloration resistance.

In the solventless adhesive of the present invention, the proportion of the main component copolymer polyester polyol and the curing agent polyisocyanate used is such that the molar ratio of NCO groups to OH groups (NC
The amount of O / OH) is preferably in the range of 1.5 to 2.5. If it is less than 1.5, the adhesive strength after curing will be poor, and if it exceeds 2.5, curing will be slow and aging will take time.
It also causes the generation of bubbles.

A laminated product having a constitution including a plastic film or sheet using the solventless adhesive of the present invention, a vapor-deposited plastic film or a metal foil uses a conventionally known solventless laminator, for example, one of the laminated base materials. In addition, a solvent-free adhesive consisting of the above-mentioned main component and a curing agent is used in a coating roller in which a metal roll (heating: a temperature at which the adhesive does not normally cure at about 30 to 100 ° C.) and a rubber roll are combined to form a coating roller of 0.1 to 5 g / m ^2. It is produced by applying it to a thickness of about 2 times and passing this and the other base material through a laminating unit consisting of a rubber roll and a metal roll and aging for about 12 to 60 hours at a temperature of about 30 to 50 ° C. to accelerate curing. can do. By using the solventless adhesive of the present invention, a composite laminate film or sheet having an excellent appearance is formed. At this time, it is preferable to heat-treat after applying the solventless adhesive and before laminating, whereby a laminated product having an excellent appearance can be obtained.

[0020]

EXAMPLES The present invention will be specifically described below with reference to Examples and Comparative Examples. In addition,% in the following text is based on weight. The content of hydroxyl group in the polyester polyol is J
It was measured according to IS K007. The weight average molecular weight is the molecular weight in terms of standard polystyrene measured by GPC.

Production Example 1 (Synthesis of Copolymerization Polyester Polyol Main Agent) 332 g of isophthalic acid, 438 g of adipic acid, 1,4-
Cyclohexanedimethanol 144 g, diethylene glycol 133 g and 1,6-hexanediol 413 g
Was charged in a 2-liter 4-necked flask and heated to 230 ° C. for 5 hours with stirring under a nitrogen stream, and an esterification reaction was carried out while distilling water. When the distillation stops,
Add 0.1 g of stannous octoate and raise the temperature to 250 ° C.
Polycondensation was carried out under reduced pressure of 0 torr to obtain a polyester polyol base compound (a) having a hydroxyl group content of 2.0%. This polyester polyol had an isophthalic acid / adipic acid molar ratio of 40/60 (1,4-cyclohexanedimethanol and 1,6-hexanediol) / diethylene glycol molar ratio of 72/28 and a weight average molecular weight of 1700.
Met.

Production Example 2 (Synthesis of Copolymerization Polyester Polyol Main Agent) Isophthalic acid 249 g, sebacic acid 707 g, 1,6-
Hexanediol 295g, diethylene glycol 10
6 g and 124 g of ethylene glycol were placed in a 2-liter 4-necked flask and heated to 230 ° C. for 5 hours while stirring under a nitrogen stream, and an esterification reaction was carried out while distilling water. When the distillation was stopped, 0.1 g of stannous octylate was added, the temperature was raised to 250 ° C., polycondensation was carried out under reduced pressure of 30 Torr, and the polyester polyol base agent (b) having a hydroxyl group content of 1.7% was obtained. Obtained. The molar ratio of isophthalic acid / sebacic acid of this polyester diol is 30/70.
(1,6-hexanediol and ethylene glycol) /
The molar ratio of diethylene glycol was 78/22, and the weight average molecular weight was 2000.

Production Example 3 (Preparation of Polyisocyanate Hardener) 100 parts by weight of Duranate TPA-100 [made by Asahi Kasei: hexamethylene diisocyanate polyisocyanate] Shin-Etsu Silicone KBE-9007 [made by Shin-Etsu Chemical Co., Ltd .: isocyanate functional silane] 0.8 part by weight was added to obtain a polyisocyanate curing agent A having an isocyanate group content of 21.9%.

Example 1 A two-component supply device in which the weight ratio of the main agent (a) obtained in Production Example 1 to the curing agent A obtained in Production Example 3 was adjusted to 60 ° C. in a weight ratio of 10: 4, Using a mixer and a squeeze roll type coater, apply 2.0 g / m ² to a biaxially stretched nylon film having a thickness of 25 μm, smooth the surface with a smoothing roll heated to 90 ° C., and then apply a thickness of 0. A 2 mm polyethylene sheet was attached, left at 40 ° C. for 48 hours, and then subjected to a T-type peeling test according to JIS K6854. Table 1 shows the test results together with the contents of the main agent and the curing agent. The same applies to the other examples and comparative examples.

Example 2 The main agent a obtained in Production Example 1 and the curing agent A obtained in Production Example 3 were adjusted to a temperature of 60 ° C. in a weight ratio of 10: 2.
Using a liquid supply device, a mixer, and a squeeze roll type coater, apply 2.0 g / m ² to a silica vapor-deposited polyethylene terephthalate film having a thickness of 12 μm, and 120 ° C.
After heat treatment for 1 second in a hot air drying furnace of No. 6, a polyethylene film having a thickness of 60 μm was stuck, left at 40 ° C. for 48 hours, and then subjected to a T-type peeling test according to JIS K 6854.

Example 3 The main agent (b) obtained in Production Example 2 and the main agent (b) obtained in Production Example 3
Hardening agent A was adjusted to a temperature of 60 ° C in a weight ratio of 10: 4.
2 liquid supply device, mixer, squeeze roll type coating
25-meter-thick biaxially stretched nylon film
2.0 g / m ² Smoothin coated and heated to 90 ℃
After smoothing the surface with groll, a 0.2 mm thick poly
Laminate ethylene sheets and leave at 40 ° C for 48 hours
After that, a T-type peel test is performed according to JIS K 6854.
It was.

Example 4 The main agent b obtained in Production Example 2 and the curing agent A obtained in Production Example 3 were adjusted to a temperature of 60 ° C. in a weight ratio of 10: 2.
Using a liquid supply device, a mixer, and a squeeze roll type coater, apply 2.0 g / m ² to a silica vapor-deposited polyethylene terephthalate film having a thickness of 12 μm, and 120 ° C.
After heat treatment for 1 second in a hot air drying furnace of No. 6, a polyethylene film having a thickness of 60 μm was stuck, left at 40 ° C. for 48 hours, and then subjected to a T-type peeling test according to JIS K 6854.

Comparative Example 1 The molar ratio of aromatic dicarboxylic acid to aliphatic dicarboxylic acid was 0.
/ 100 was used to prepare a solventless adhesive in the same manner as in Example 1 to obtain a laminate, and JIS K6854 was used.
The T-type peeling test was performed according to the above.

Comparative Example 2 The molar ratio of aliphatic diol and dialkylene diol was 1
A solventless adhesive was prepared in the same manner as in Example 1 except that it was set to 00/0 to obtain a laminated product, and JIS K6854 was used.
The T-type peeling test was performed according to the above.

Comparative Example 3 A solvent-free adhesive was prepared in the same manner as in Example 1 except that a polyisocyanate having an isocyanate content of 10% or less, which was outside the scope of the present invention, was used to obtain a laminated product.
A T-type peel test was performed according to K 6854.

Comparative Example 4 A non-sol bond XC-235 (polyether-based main agent (c)) manufactured by Dainichi Seika Co., Ltd., which is a polyether-based urethane solvent-free adhesive, and a non-sol bond XA-129 (prepolymer-based curing agent B) are also used. Using a two-liquid feeder, a mixer, and a squeeze roll type coater, the weight ratio of which is 10: 4 and the temperature of which is adjusted to 60 ° C., 2.0 g / m ^{2 is} applied to a biaxially stretched nylon film having a thickness of 25 m. Immediately, attach a polyethylene sheet with a thickness of 0.2 mm to 40 ° C.
After leaving it for 48 hours at T, it is tested according to JIS K6854.
A mold peeling test was conducted.

Comparative Example 5 The main agent (c) and the curing agent B were mixed at a weight ratio of 10: 4 at 60 ° C.
2.0g / m on a silica-deposited polyethylene terephthalate film with a thickness of 12μm, using a two-liquid supply device whose temperature is adjusted to 1, a mixer, and a squeeze roll type coater.
^{2 After} coating, immediately apply a polyethylene film with a thickness of 60 μm, leave it at 40 ° C for 48 hours, and then JIS
A T-type peel test was performed according to K 6854.

[0033]

[0034]

EFFECT OF THE INVENTION According to the present invention, a solventless adhesive capable of producing a laminated product which is environmentally friendly, has excellent durability, and has a high adhesive strength, a laminated product including a plastic sheet or film, a vapor-deposited plastic film or a metal foil. Will be provided.

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Masafumi Saito             1-7-6 Nihonbashi Bakurocho, Chuo-ku, Tokyo Large             Within Nissei Chemical Co., Ltd. F term (reference) 4F100 AA20 AK04 AK42 AK48 AK51C                       AL01C AT00A AT00B BA03                       BA10A BA10B CA02C EC03                       EH46 JL11C YY00C                 4J034 BA03 DA01 DB03 DH01 DH06                       HA01 HA07 HC03 HC12 HC17                       HC22 QA03                 4J040 EF111 EF291 EF301 GA05                       GA20 LA07 MA02 MA10 NA08

Claims (5)

[Claims] 1. A solventless adhesive comprising a main component of polyester polyol and a curing agent of polyisocyanate,
The polyester polyol has a hydroxyl group content of 0.5 to 6.
It is a copolymer polyester polyol of 0% by weight, and the polyisocyanate has an isocyanate group content of 10 to 3
A solventless adhesive characterized in that it is 0% by weight. 2. A copolymer type polyester polyol,
A copolymerized polyester polyol of (1) an aromatic and / or alicyclic dicarboxylic acid, and an aliphatic dicarboxylic acid, and (2) an aliphatic diol and / or an alicyclic diol, and a dialkylene diol. The solventless adhesive described in 1. 3. The solventless adhesive according to claim 1, wherein the polyisocyanate is at least one selected from aliphatic polyisocyanates, alicyclic polyisocyanates, and condensation products thereof. 4. The use ratio of the main agent and the curing agent is NCO / O.
The solventless adhesive according to any one of claims 1 to 3, wherein the H (molar ratio) is in a range of 1.5 to 2.5. 5. A method for laminating, wherein the solvent-free adhesive according to claim 1 is used when laminating a sheet-shaped or film-shaped substrate.