JP2003082324A - Solventless lamination adhesive composition and lamination method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a solventless lamination adhesive composition suffering from no viscosity changes accompanying changes in a compounding ratio and excellent in coating aptitude, adhesive force just after lamination and lamination strength after cure, and to provide a lamination method. SOLUTION: The solventless lamination adhesive composition is obtained by compounding a polyester polyol (A), which comprises a mixture of (a) one obtained using a starting material containing 30 wt.% or less of an aromatic polybasic carboxylic acid with (b) one obtained using a starting material containing 30-50 wt.% of an aromatic carboxylic acid, with a polyisocyanate (B), which is obtained by modifying (a) and/or (b) with at least one polyisocyanate bearing an isocyanurate skeleton and a biuret bond, where both (A) and (B) have a viscosity of 3,000 cP or less at 80 deg.C, exhibit viscosity increase of at least 3,000 cP per degree of decrease in temperature during temperature decrease from 40 deg.C to 30 deg.C and have a viscosity of at least 75,000 cP at 25 deg.C.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a solvent-free adhesive composition for lamination for compounding plastic films, a plastic film and a metal foil such as aluminum, and a metal vapor deposition film.

[0002]

2. Description of the Related Art Laminated films are used for foods, pharmaceuticals,
Widely used as a packaging material for detergents. In pasting films, most of the past is a dry lamination method in which an adhesive dissolved in an organic solvent is applied to the film, the organic solvent is volatilized while passing through an oven, and another film is pasted. However, the movement toward desolventization is becoming active due to various problems caused by working environment measures and organic solvents. However, although the solventless adhesive solves these problems related to the environment and the like, it is necessary to take a method of lowering the molecular weight and lowering the viscosity of the adhesive composition in order to improve the coating suitability. In this case, since the low-molecular-weight adhesive having a reduced viscosity has a low viscosity and a low molecular weight, there is still a problem that the strength of the films immediately after the bonding is insufficient when the films are bonded together. In addition, the type of film, the type of ink on the printing film, and the heat resistance required, etc.
In liquid adhesives, the compounding ratio of the base material and the curing agent is often intentionally changed. For solventless adhesives,
When the viscosities of the main agent and the curing agent are different, the change in the compounding ratio leads to a marked change in the viscosity of the adhesive. In the coating of a solventless adhesive, there is a characteristic that the coating amount changes depending on the properties of the coating machine, particularly depending on the viscosity at the time of coating. Under the present circumstances, the viscosity is changed, and in particular, various problems are caused due to the adhesive ability immediately after the bonding and the coating amount deviation.

[0003]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the inventors of the present invention have satisfied the coating suitability and did not cause winding deviation immediately after bonding. Furthermore, the main agent and the curing agent are blended. It is an object to provide an extremely practical solvent-free lamination adhesive that has almost no change in viscosity due to a change in ratio, is excellent in coating stability, and has sufficient adhesive strength.

[0004]

Means for Solving the Problems The inventors of the present invention have earnestly studied a method of improving coating stability and leveling property and enhancing the adhesive ability immediately after bonding. As a result, the polyester polyol (A) and polyisocyanate (B ) Is 80 ℃
Viscosity is less than 3000 cP at 40 ℃ to 30 ℃
When the temperature drops to 3,000, the viscosity increases by more than 3000 cP / ° C.
It has been found that a two-liquid solventless lamination adhesive composition having a viscosity at 5 ° C. of 75,000 cP or more is a method for solving this problem. That is, at the temperature at which the adhesive is applied, it exhibits fluidity and leveling properties with sufficient coating suitability, and after bonding, the adhesive strength of the adhesive cooled to around room temperature increases and the winding of the laminated composite is increased. It is intended to provide a two-component solvent-free lamination adhesive composition which does not cause misalignment and which can also satisfy the laminate strength after curing. More specifically, the polyester polyol (A) is a polyester polyol (a) containing 30% by weight or less of an aromatic polycarboxylic acid used as a raw material, and a polyester polyol (b) containing 30 to 50% by weight. And a solvent-free lamination adhesive composition containing as a curing agent a polyisocyanate (B) component containing at least one selected from the group of polyisocyanate components containing an isocyanurate skeleton and a burette bond. It is a thing, 8
The adhesive composition heated to 0 ° C. has a low viscosity of 3000 cP or less and thus has excellent coating suitability, and when the temperature changes from 40 ° C. to 30 ° C., the viscosity increases by 3000 cP / ° C. or more, and at 25 ° C. A new two-component solvent-free lamination adhesive composition that has excellent strength immediately after lamination and can also exhibit a winding misalignment prevention effect by combining the characteristics of 75,000 cP or more, and a lamination method using the same adhesive It was developed.

[0005]

BEST MODE FOR CARRYING OUT THE INVENTION The polyester polyols (a) and (b) according to the present invention can be produced by a reaction known in the art. Specifically, it can be obtained by a dehydration condensation reaction, a transesterification, or a ring-opening reaction of a polyhydric alcohol with a polycarboxylic acid or an acid anhydride. Examples of the polyhydric alcohol include diol components such as ethylene glycol, propylene glycol, diethylene glycol, 1,4-butanediol, 1,6-hexanediol, and neopentyl glycol, glycerin, trimethylolpropane, trimethylolpropane, pentaerythritol, Polyhydric alcohols such as sorbitol can be used.
The polycarboxylic acid is roughly classified into an aliphatic polycarboxylic acid and an aromatic polycarboxylic acid, and in the aliphatic system, succinic acid, maleic acid, adipic acid, azelaic acid, sebacic acid, dimer acid, etc. Of the aliphatic dicarboxylic acids and, in some cases, these methyl esters and acid anhydrides, and in the aromatic system, phthalic acid, isophthalic acid, terephthalic acid, trimellitic acid, pyromellitic acid, etc. The methyl ester or acid anhydride thereof can be used.

When the polyester polyols (a) and (b) are described by component, the polyester polyol (a) contains the above aromatic polycarboxylic acid in an amount of 30% by weight or less, preferably 15 to 30% by weight, based on the total amount of the raw materials charged. In the polyester polyol (b), the aromatic polycarboxylic acid is 30 to 50% by weight, preferably 35 to 45% by weight, based on the total amount of the raw materials charged. The resin acid value of each polyester polyol (a) and (b) is not particularly limited, but the acid value of (a) is preferably 5 mgKOH / g or less. When it is 5 mgKOH / g or more, the leveling property during coating may be deteriorated. The resin acid value of the polyester polyol (b) is preferably 2 to 20 mgKOH / g, and particularly contributes to the improvement of the adhesive force to the aluminum foil and the retort resistance. However, when it is 20 mgKOH / g or more, it may adversely affect water resistance and alkali resistance. The molecular weight of each polyester polyol (a) and (b) is not particularly limited as long as it is within the range of each viscosity specified in the present invention, but the number average molecular weight of (a) is 500 to 50.
00, and preferably 800 to 2000.
The number average molecular weight of (b) is 400 to 2000, preferably 600 to 1500.

Further, the polyester polyols (a) and / or (b) may be preliminarily chain-lengthened with polyisocyanate, if necessary. The polyisocyanate that can be used is not particularly limited, and examples of the diisocyanate include 1,6-hexamethylene diisocyanate, isophorone diisocyanate, m-xylylene diisocyanate, α, α, α′α′-tetramethyl-m-
Xylylene diisocyanate, norbornene diisocyanate, 2,4-tolylene diisocyanate, 2,6-
Tolylene diisocyanate, 1,5-naphthalene diisocyanate, 4,4'-diphenylmethane diisocyanate, 2,4'-diphenylmethane diisocyanate, and the like, and as polyfunctional polyisocyanates, these burettes, nurates, and tri Examples thereof include a methylolpropane adduct and the like, and one or more selected from these groups can be used. However, it is essential to remove the organic solvent in advance from the polyisocyanate diluted with the organic solvent.

The polyester polyol (A), which is a mixture of the polyester polyols (a) and (b) thus obtained, has a viscosity at 80 ° C. of not more than 3000 cP (more specifically, preferably in the range of 3000 cP to 800 cP). And when the temperature drops from 40 ° C to 30 ° C, 3
000 cP / ° C or higher (more specifically, 300
Viscosity increase of 0 cP to 50,000 cP), 25
Viscosity at ℃ 75000cP or more (more specifically, within the range of 75000cP to 500000cP)
It is necessary to meet each condition of. When the polyester polyols (a) and (b) constituting the polyester polyol (A) satisfy the respective viscosity / temperature conditions, there are no particular restrictions on the combination of (a) and (b). Even if at least one of (a) and (b) deviates from the respective conditions, the polyester polyol (A) as a whole may satisfy the above viscosity / temperature conditions. For example, when it is necessary to enhance the leveling property and the adhesiveness immediately after bonding, even if one or both of (a) and (b) deviates from the respective conditions, the polyester polyol ( A) It can be compounded so as to satisfy the above viscosity / temperature conditions as a whole. The formulation often satisfies each condition within the range of the weight ratio of (a) :( b) = 1: 4 to 4: 1.
Within the temperature conditions, the viscosity at 80 ° C becomes lower,
It is desirable to adjust the compounding ratio so that the viscosity increase at the temperature change from 40 ° C. to 30 ° C. is larger and the viscosity at 25 ° C. is higher. As described above, the polyester polyol (A) of the present invention is the above polyester polyol (a).
It is preferable to carry out as a mixture of (b) and (b), but it is also possible to carry out as one kind of polyester polyol or as a mixture of three or more kinds of polyester polyols.

Furthermore, the polyester polyol (A) obtained by the present invention (the above polyester polyol (a))
To the mixture (A)) of (b) and (b), a silane coupling agent known as a known adhesion-imparting agent, phosphoric acid, a tackifier, a reaction accelerator, etc. can be appropriately added, if necessary.

As the silane coupling agent, γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropylmethyldimethoxysilane, γ- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, γ
-Aminopropyltrimethoxysilane, γ-aminopropylmethyldimethoxysilane, N-β (aminoethyl)
-Γ-aminopropyltrimethoxysilane, N-β (aminoethyl) -γ-aminopropylmethyldimethoxysilane, γ-mercaptopropyltrimethoxysilane, γ
Examples thereof include mercaptopropylmethyldimethoxysilane and ethoxy derivatives thereof, and one or more selected from these groups can be used.

Examples of phosphoric acids include orthophosphoric acid, metaphosphoric acid, polyphosphoric acid and their ester derivatives, and one or more selected from these groups can be used.

As the tackifier, any of rosin type, terpene type and petroleum type can be used.

These additives can be added within the range of each viscosity / temperature condition of the present invention.

As the reaction accelerator, known compounds can be used, and examples thereof include metal catalysts such as dibutyltin diacetate, dibutyltin dilaurate, dioctyltin dilaurate and dibutyltin dimalate, and 1,8-diaza-bicyclo (5,4). , 0) Undecene-7,1,5-diazabicyclo (4,3,0) nonene-5,6-dibutylamino-1,8-diazabicyclo (5,4,0) undecene-
Examples thereof include tertiary amines such as 7 and reactive tertiary amines such as triethanolamine, and one or more selected from these groups can be used.

Next, the polyisocyanate (B) which is a curing agent component will be described. It is essential that the curing agent that can be used is a polyisocyanate that does not contain an organic solvent as a mere diluent, and further, at least 1 selected from the group of polyisocyanate components containing an isocyanurate skeleton and a burette bond. It is desirable that the polyisocyanate (B) component contains one or more kinds.

Polyisocyanate containing an organic solvent must be desolvated in advance. In this case, it is desirable to carry out a treatment such as thin film distillation for the purpose of removing the organic solvent, but complete solvent removal is difficult, so it is more preferable not to use a solvent in the production of polyisocyanate as much as possible.

As the polyisocyanate containing an isocyanurate skeleton or a burette bond, the kind of the diisocyanate as a base is not particularly limited, but in consideration of heat resistance and versatility, for example, 1,6-hexamethylene diisocyanate is used. And derivatives derived from isophorone diisocyanate.

These isocyanurate skeleton-containing and biuret bond-containing polyisocyanate components may be used alone or as a mixture, or may be used as a polyisocyanate body reacted with a polyol. Furthermore, a polyisocyanate body obtained by reacting a diisocyanate and a polyisocyanate component having an isocyanurate skeleton or a burette bond with a polyol can be used.

As the diisocyanate, 1,6-hexamethylene diisocyanate, isophorone diisocyanate, m-xylylene diisocyanate, α, α, α '
α'-tetramethyl-m-xylylene diisocyanate, norbornene diisocyanate, 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, 1,5-naphthalene diisocyanate, 4,4'-
Examples thereof include diphenylmethane diisocyanate and 2,4′-diphenylmethane diisocyanate, and one or more selected from these groups can be used.

Polyols that can be used for producing the polyisocyanate (B) as a curing agent include ethylene glycol, diethylene glycol, propylene glycol,
Dipropylene glycol, 1,4-butanediol, neneopentyl glycol, 1,6-hexamethylene glycol, 1,8-octamethylene glycol, 1,4-
Dihydric alcohols such as cyclohexanedimethanol, polyhydric alcohols such as trimethylolpropane, trimethylolethane, glycerin and pentaerythritol,
Polyester polyols obtained from these polyols and polyvalent carboxylic acids, polyether polyols such as polyethylene glycol, polypropylene glycol, polytetramethylene glycol, and the like can be mentioned. Use of one or more selected from these groups In particular, a curing agent obtained by subjecting the polyester polyols (a) and / or (b) obtained by the present invention to isocyanate modification, and further, the above-mentioned polyols added to (a) and / or (b) before being isocyanate modified. A hardener is preferred.

Further, in the production of polyisocyanate (B), a monool component may be reacted for the purpose of adjusting the number of functional groups. The monool is not particularly limited, and may be methanol, ethanol, 1-propanol, 2-
Propanol, 1-butanol, 2-butanol, 1-
Hexanol, 1-octanol and the like can be mentioned, and one or more selected from these groups can be used.

Known catalysts can be used, if necessary, even during the production of the curing agent, and examples thereof include metal catalysts such as dibutyltin diacetate, dibutyltin dilaurate, dioctyltin dilaurate and dibutyltin dimalate. One or two or more selected from these groups can be used.

The viscosity of the polyisocyanate (B), which is a curing agent, is the same as that of the polyester polyol (A) at 80 ° C.
3,000 cP or less, viscosity increase at temperature drop from 40 ° C to 30 ° C is 3000 cP / ° C or more, 7500 at 25 ° C
It is within the range of 0 cP or more (the same as the above-mentioned polyester polyol (A) in a more specifically desirable range). When the polyester polyol (A) and the polyisocyanate (B) have the same viscosity, it is not necessary to consider the change in viscosity due to the change in the compounding ratio, so that the laminating conditions can be the same and the change in the compounding ratio can be performed. Insufficient initial strength and defects in the appearance of the laminate caused by the above are eliminated. Generally, it is unavoidable to change the mixture ratio of the main agent / curing agent for the purpose of responding to changes in film type and humidity in the laminating environment. However, since it is possible to cope with such changes in the mixture ratio, (A) and ( It is extremely effective to keep B) within the same viscosity specification. However,
If the coating conditions do not change the compounding ratio, it is not necessary to set (A) and (B) within the same viscosity regulation,
The viscosity just after blending (A) and (B) should be within the viscosity regulation of the present invention.

As a laminating method, the temperature of the compounded adhesive during coating is preferably 50 to 100 ° C., more preferably about 50 to 80 ° C., and the viscosity of the adhesive immediately after compounding is 3000 cP or less. However, if the viscosity is higher than the above range, the coating stability may be poor, and the appearance may be poor or the adhesive strength may be poor.

The coating amount is about 0.5 to 5 g / m ² , preferably about 1.5 to 3.5 g / m ² . When the coating amount is less than 0.5 g / m ² , sufficient expression of adhesive performance may be impaired, and appearance defects such as scratches may occur. If it exceeds 5 g / m ² , it is disadvantageous in terms of economy. Generally, the laminated film usually requires curing at room temperature to 50 ° C. for 2 to 5 days.

[0026]

EXAMPLES The present invention will be described in more detail with reference to examples below, but the present invention is not limited to the following examples.

Main agent: Polyester polyol (a) -1
In a flask equipped with a synthetic stirrer, a thermometer, a nitrogen gas inlet tube, a rectification column, and a condenser, neopentyl glycol (180.3 parts) and ethylene glycol (53.8 parts).
Part), 1,6-hexanediol (204.6 parts), isophthalic acid (287.8 parts g), adipic acid (273.
5 g) was charged and heated. When the raw materials began to melt, stirring was carried out, and the reaction was carried out at an internal temperature of 240 ° C. until the acid value became 10 mgKOH / g or less so that the temperature in the upper part of the rectification column did not exceed 100 ° C. Furthermore, the reaction was continued at 30 mmHg until the acid value became 3 mgKOH / g or less. The acid value of the obtained polyester polyol (a) -1 is 3 mgKOH.
/ G.

Other polyester polyols (a)-
2, (b) -1 and (b) -2 were synthesized by performing the same reaction as in (a) -1 with the charged amounts shown in Table 1 until the final acid value was reached. Table 1 also shows the weight% of the aromatic polycarboxylic acid used in the synthesis of each polyester polyol in the charged raw materials.

Curing agent: Synthesis of polyisocyanate (B) -1 A polyester flask (a) -1 (17) obtained above was placed in a flask equipped with a nitrogen introducing device and a thermometer.
0.0 part) and Asahi Kasei TPA-100 (nurate of 1,6-hexamethylene diisocyanate) (300.
(0 part) was charged, and the reaction was carried out under a nitrogen atmosphere at an internal temperature of 80 ° C. for 3 hours.

As a comparative example of polyisocyanate which is a curing agent, Duranate TPA-100 manufactured by Asahi Kasei Corporation
(Nurate body of 1,6-hexamethylene diisocyanate) was used.

Evaluation Polyester polyols (a) and (b) each alone, a mixture of (a) and (b), and polyisocyanate (B) were adjusted at the compounding ratios shown in Table 2 to measure the respective viscosities. Moreover, the viscosity measurement with the temperature change from 40 ° C. to 30 ° C.
The viscosity was continuously measured while lowering the temperature of 1 ° C. per minute. The increase in viscosity when the temperature changes from 40 ° C to 30 ° C
(40 ° C. viscosity-30 ° C. viscosity) / 10 derived.

Measurement of Initial Strength As shown in Table 3, the main component (A) and the curing agent (B) were mixed and the initial strength was measured. In this initial strength measuring method, in consideration of the winding deviation after lamination, as shown in FIG. 1, the film 1 and the film 2 were laminated such that the area of the bonded portion 3 was 1 inch × 1 inch. . ONy was used for the film 1 and LLDPE was used for the film 2. The coating amount is 3.0 g / m ² . Immediately after lamination, the tensile strength of the laminate film in the longitudinal direction was measured at 25 ° C. using a tensile tester at a crosshead speed of 5 mm / min.

Measurement of Normal Strength As shown in Table 2, the main agent (A) and the curing agent (B) were blended and ONy and LLDPE were laminated. The coating amount is 3.0 g / m ² . This was cured at 40 ° C for 3 days, and the T-type peel strength of the laminated part in the width of 15 mm was 25
Crosshead speed 300m using tensile tester at ℃
It was measured at m / min.

The materials and equipment used in the test are as follows. ONy Film: Unitika Emblem ONRT
ONBC-RT 25 μm LLDPE film: TUX-FCD 6 manufactured by Tohcello Co., Ltd.
0 μm tensile tester: Autograph AG-2 manufactured by Shimadzu Corporation
000C Viscometer: RS-150 (Viscoelasticity measuring device manufactured by HAAKE, Germany)

Table 3 shows the evaluation results of the adhesives produced and compounded according to the present invention. As is clear from the respective evaluation results, the examples of the present invention showed good results in all of the appearance, initial strength, and normal strength as compared with the comparative examples. In particular, as is clear from the results of Examples 3 and 4, it was confirmed that good results were obtained even when the blending ratio of the polyester polyol (A) and the polyisocyanate (B) was changed. .

[0036]

[Table 1]

[0037]

[Table 2]

[0038]

[Table 3]

[0039]

In the adhesive composition for solventless lamination according to the present invention, each of the polyester polyol (A) and the polyisocyanate (B) is 8
Viscosity at 0 ° C. is 3000 cP or less, low viscosity, good coating stability and leveling property, and excellent laminate appearance. Further, since there is almost no change in viscosity due to a change in the mixing ratio of the main agent / curing agent, it is possible to laminate under the same coating conditions even when the mixing ratio is changed. Also, from 40 ° C to 30
Viscosity increase when the temperature drops to ℃ is 3000 cP / ℃ or more, and viscosity at 25 ℃ is 75000 cP or more, so the adhesive strength is high immediately after bonding, and it is also effective as a measure against winding deviation after lamination. To do. Thus, the solvent-free lamination adhesive composition of the present invention,
(1) low viscosity at high temperature range, (2) high viscosity increase due to temperature change to low temperature, and (3) final properties can be obtained even if the main agent and curing agent have the same viscosity. There are three problems that are difficult to solve at the same time: (1) excellent line suitability, leveling property, (2) effect of preventing winding misalignment during winding, and (3) realizing safer and more durable laminating. The present invention can be realized by a solventless laminating adhesive and a laminating method using the adhesive.

[Brief description of drawings]

FIG. 1 is an explanatory view of a method for measuring an initial strength, (A) is a front view and (B) is a longitudinal sectional view.

[Explanation of symbols]

1 film 2 films 3 pasted part

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Masaki Takemori             2-37-2 Minamisuna, Koto-ku, Tokyo Rock             Paint Co., Ltd. Tokyo Branch (72) Inventor Naoki Matsumoto             2-37-2 Minamisuna, Koto-ku, Tokyo Rock             Paint Co., Ltd. Tokyo Branch (72) Inventor Toshio Nakamura             2-37-2 Minamisuna, Koto-ku, Tokyo Rock             Paint Co., Ltd. Tokyo Branch F term (reference) 4J040 EF111 EF291 EF301 LA05                       LA06 LA08 MA02 MA10 NA08                       PA30

Claims (6)

[Claims] 1. In a solventless lamination adhesive composition used by blending a polyester polyol (A) and a polyisocyanate (B), both the polyester polyol (A) and the polyisocyanate (B) are at 80 ° C.
The viscosity is 3000 cP or less, the viscosity increase at the time of temperature decrease from 40 ° C. to 30 ° C. is 3000 cP / ° C. or more, and the viscosity at 25 ° C. is 75000 cP or more, the solventless lamination adhesive composition. 2. The polyester polyol (A) component is
30% by weight of aromatic polycarboxylic acid used as raw material
The polyester polyol (a) below is a mixture of the polyester polyol (b) whose aromatic polycarboxylic acid used as a raw material is 30 to 50% by weight. Solvent-based lamination adhesive composition. 3. The solventless lamination adhesive composition according to claim 2, wherein at least one of the polyester polyols (a) and (b) has a urethane chain length. 4. The solvent-free composition according to claim 1, wherein the polyisocyanate (B) component contains at least one selected from the group of polyisocyanate components containing an isocyanurate skeleton and containing a biuret bond. Type lamination adhesive composition. 5. The solventless lamination according to any one of claims 1 to 4, wherein the polyisocyanate (B) component is modified with the polyester polyols (a) and / or (b). Adhesive composition. 6. The solventless lamination adhesive composition according to claim 1, which is applied under the condition that the temperature of the compounded adhesive during application is 50 ° C. or higher. Laminating method.