JPS63270782A - Adhesive composition - Google Patents

Abstract

PURPOSE:To provide an adhesive compsn. which has excellent low-temp. adhesiveness, water resistance and peeling strength, and which comprises a particular polyester resin, a hydrophobic silica and a polyisocyanate compd. CONSTITUTION:At least 50wt.% polyester resin having a number-average MW of 5,000-25,000 and a glass transition temp. of 50-80 deg.C, 5-50wt.% hydrophobic silica having a particle size of 0.005-20mum and a specific surface area of 50-300m<2>/g, 0.1-50wt.% polyisocyanate compd. [e.g., methylenebis(4-phenyl isocyanate)], and optionally 0.1-10wt.% ethyleneimine or diazabicycloundecene crosslinking agent [e.g., 1,8-diazabicyclo(5,4,0)-7-undecene] are mixed together. The viscosity of the compsn. is regulated by addn. of a ketone solvent (e.g., toluene).

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an adhesive composition, and more particularly, to a polyester-based adhesive composition used for bonding a vinyl chloride film and a metal plate, etc. The present invention relates to improving the adhesive performance of adhesive compositions.

[Invention (already required)]

The present invention enables low-temperature adhesion, has high peel strength, and has water resistance and Close call transferability (I
The present invention aims to provide an adhesive composition that has been developed.

[Conventional technology]

-a, the vinyl chloride film and a metal plate such as an iron plate or a zinc plate are bonded together using an adhesive.

Conventionally, acrylic adhesives, polyester adhesives, and the like are mainly known as the above-mentioned adhesives.

However, since the above-mentioned acrylic adhesive is mainly composed of methyl meccrylate polymer, which has a high glass transition temperature, high-temperature lamination is required to bond the vinyl chloride film to the metal plate. The vinyl chloride film mentioned above does not have very high heat resistance, so if, for example, a vinyl chloride film with various patterns embossed on its surface is laminated at high temperature, the pattern may disappear or the vinyl chloride film may The problem arises that the smoothness of the film surface becomes high and the appearance is impaired, such as gloss, resulting in a decrease in the value of products made of vinyl chloride film processed on metal plates.

On the other hand, polyester adhesives allow lamination bonding at relatively low temperatures compared to acrylic adhesives, and the product value for one piece in terms of appearance is maintained. However, this polyester adhesive generally has low water resistance; for example, when peel strength is measured after conducting a water conduction test, the result is much lower than the initial value immediately after lamination, causing problems in terms of weather resistance and reliability. occurs.

[Problem that the invention seeks to solve]

As described above, when adhering a vinyl chloride film to a metal plate, using an acrylic adhesive that requires high-temperature lamination causes problems in that the appearance is impaired and the commercial value is reduced. Furthermore, polyester adhesives that can be laminated at low temperatures do not impair the appearance, but have poor water resistance, which poses problems in terms of reliability.

Therefore, our objective is to take advantage of the low-temperature adhesion properties that are an advantage of polyester adhesives, add water resistance and high peel strength to them, and provide an adhesive composition that has excellent adhesion properties. .

[Means for solving problems]

The present inventors have conducted intensive research over a long period of time to develop a polyester adhesive that has water resistance and high peel strength, and have found that hydrophobic silica is useful for imparting water resistance. It has been found that mixing this into a polyester adhesive and further adding a polyisocyanate compound can effectively improve water resistance and peel strength.

The present invention was completed based on such knowledge, and the composition of the adhesive has a glass transition temperature T0 of 50.
~80°C polyester resin 50% or more, hydrophobic silica 5-50% by weight, polyisocyanate compound 0.
It is characterized by consisting of 1 to 50% by weight.

In the adhesive composition of the present invention, the main polyester resin is synthesized by reacting a polyhydric alcohol and a polybasic acid in a predetermined ratio.

Examples of the polyhydric alcohol used include ethylene glycol, diethylene glycol, propylene glycol 51,4 butanediol, neopentyl glycol,
l, 4 cyclohexane dimetatool and the like.

Further, as the polybasic acid, for example, isophthalic acid.

Examples include aromatic dicarboxylic acids such as terephthalic acid, aliphatic dicarboxylic acids such as adipic acid, and sebacic acid.

The polyester resin synthesized from the polyhydric alcohol and polybasic acid has a number average molecular weight of about 5,000 to 25,000.
It is desirable that the temperature and glass transition temperature T be 50 to 80°C.

Here, the reason why the number average molecular weight is about 5,000 to 25,000 is because if it is out of this range, the desired adhesive properties cannot be obtained, and the adhesive composition is crosslinked with a crosslinking agent that is added later, so that the glass transition temperature does not reach the specified value. This is because there is a possibility that the value will be higher than the value.

Moreover, the glass transition temperature T6 was set to 50 to 80°C because
If it is less than 50°C, handling at room temperature may be affected, and if it is more than 80°C, the heating temperature during bonding becomes too high, which may cause the appearance of the vinyl chloride film to be adhered to to be damaged. be.

The glass transition temperature TG of the polyester resin can be easily controlled by changing the type and blending ratio of the polyhydric alcohol and polybasic acid used. For example, neopentyl glycol 25 mol% ethylene glycol 25 mol% terephthalate acid
By making the composition 25 mol% isophthalic acid 25 mol%, the glass transition temperature is 65°C, Neopentyl glycol 25 mol% ethylene glycol 25 mol% terephthalic acid
By setting the composition to be 10 mol% isophthalic acid, 25 mol% adipic acid, and 15 mol%, the glass transition temperature is set at 50°C.

Of course, the present invention is not limited to this, and the polyhydric alcohol or polybasic acid may be selected depending on the purpose of use, and may be appropriately set so that the glass transition temperature falls within the above-mentioned temperature range.

On the other hand, hydrophobic silica is added for the purpose of imparting water resistance to adhesives mainly composed of polyester resin. This hydrophobic silica has a particle size of about 0.05 to 20 μm and a specific surface area of 50 μm, obtained by a wet method or a dry method.
For the surface of fine silica particles of ~300 f/g,
It is hydrophobically treated with an organic compound having a group reactive with silica at one end and a lipophilic group at the other end.

The surface treatment of the fine silica particles is carried out by chemically reacting and bonding the above-mentioned organic compounds. Examples of organic compounds that can be used include organosilicon compounds, such as silane coupling agents having hydrophobic organic groups. Can be mentioned.

A specific example is C,1IsSi(OCzlls)i
, C11zSi(OC211s)i, CII*
5i (QC!+3)z.

Cll:+(CHx)tsi(OCJs)s, etc.

Furthermore, dimethyl silicone oil can also be used as an organosilicon compound.

Alternatively, in addition to the silicon compounds mentioned above, titanium coupling agents and the like can also be used. As the titanium coupling agent, any conventionally known titanium coupling agent may be used.

The above polyisocyanate compound has an isocyanate group (
-N=C.0], and acts as a crosslinking agent that crosslinks through an addition reaction.

As the above-mentioned polyisocyanate compound, methylphenyl diisocyanate (MDI) type isocyanate is excellent in terms of heat resistance, for example, methylene-bis-(4-
phenyl isocyanate). Furthermore, other polyisocyanates include tolylene diisocyanate 4, 4-diphenylmethane diisocyanate, tolydine diisocyanate 8, and hexamethylene diisocyanate.

Xylylene diisocyanate Naphthylene diisocyanate 3 Lysine isocyanate, dicyclohexylmethane diisocyanate, triphenylmethane triisocyanate, tris(P-isocyanate phenyl)thiophosphate, polymethylene polyphenyl polyisocyanate, and the like.

The above-mentioned adhesive compositions may be mixed at a ratio of 50% by weight or more of polyester resin, 5 to 50% by weight of hydrophobic silica, and 0.1 to 10% by weight of polyisocyanate compound. Regarding the polyester resin, the adhesive effect deteriorates if it is less than 50% by weight, and the content of the polyester resin is determined to be 50% by weight or more because of the relationship with other additive compositions. If the hydrophobic silica is less than 5% by weight, no hydrophobic effect can be expected, and if it exceeds 50% by weight, the adhesion effect of the polyester resin to the vinyl chloride film will be inhibited. If the polyisocyanate compound contains less than 1% by weight of O, no crosslinking effect can be expected, and if it exceeds 50% by weight, the adhesive force after the boiling water resistance test will decrease due to the influence of the unreacted polyisocyanate compound.

The adhesive composition whose basic composition is the above-mentioned polyester resin, hydrophobic silica, and polyisocyanate compound further includes an ethyleneimine-based crosslinking agent and a diazabicycloundecene (DBU)-based crosslinking agent that acts as a catalyst for crosslinking. may be added.

Examples of the ethyleneimine crosslinking agent "ζ" include the following compounds.

■ 1,8-diaza-bicyclo=(5,4,0) represented by
Examples include -7-undecene (DB[J), DBU/phenol salt, DBU/octylate, DBU-p-toluenesulfonate, DBU/formate, DBU/oleate, and the like.

Other crosslinking agents such as tertiary amines are also considered to have a crosslinking promoting effect and can be used.

When adding the above-mentioned ethyleneimine-based crosslinking agent and DBU-based crosslinking agent to the above-mentioned adhesive composition, the amount added is 0.1
It is preferably ~10% by weight, and actually 0.3~10% by weight.
It is more preferable that the amount is 1% by weight. If the amount added is less than 0.1% by weight, no crosslinking effect can be expected, and if it is more than 10% by weight, the glass transition temperature of the polyester resin will become high and the low-temperature adhesion effect will be inhibited. .

The adhesive composition having the above-mentioned composition is usually used by adding a solvent to adjust the viscosity, etc., but any general-purpose solvent can be used in this case. Among these, ketone solvents such as toluene and methyl ethyl ketone are preferred. Further, the blending ratio of the solvent and the adhesive composition may be appropriately set depending on the desired viscosity and the like.

[Effect]

Adding hydrophobic silica to the adhesive composition of the present invention! - improves the hydrophobicity of the adhesive, ensures adhesion even after the spring water test, and improves water resistance.

In addition, we controlled the glass transition temperature by changing the combination and ratio of polyhydric alcohols and polybasic acids used when synthesizing polyester resin, and increased the temperature range from 50 to
By setting the temperature to 80°C, low-temperature adhesion becomes possible.

〔Example〕

Hereinafter, specific examples of the present invention will be described, but the present invention is not limited to these examples.

Example 1 First, 25 mol% of neopentyl glycol, 25 mol% of ethylene glycol, 25 mol% of terephthalic acid and 25 mol% of isophthalic acid were reacted to a glass transition temperature of 65"C.
A polyester resin A was synthesized.

Then, a composition mainly composed of polyester resin A shown below was mixed to obtain an adhesive composition.

Polyester resin A 100 parts by weight Polyisocyanate compound 5 parts by weight (manufactured by Nippon Polyurethane Co., Ltd., trade name: Millionate MR) Hydrophobic silica 25 parts by weight (manufactured by Nippon Silica Co., Ltd., trade name: Futsubushiru E-20OA - methyltriethoxysilane treatment) Ethylene Imine crosslinking agent 1 part by weight (manufactured by Nippon Shokubai Kagaku Co., Ltd., trade name TAZ: ω-aziridinylpropionic acid-2,2-dihydroxylmethylbutanol ester) Toluene 150 parts by weight Methyl ethyl ketone 150 parts by weight Example 2 First , 25 mol% neopentyl glycol, 25 mol% ethylene glycol, 25 mol% terephthalic acid.

and 25 mol% of isophthalic acid were reacted to synthesize polyester resin A having a glass transition temperature of 65°C.

On the other hand, 50 mol% of neopentyl glycol, 5 mol% of dimethyl terephthalate H, 15 mol% of dimethyl isophthalate and 20 mol% of succinic anhydride were reacted to synthesize polyester resin B having a glass transition temperature of 5°C.

Then, a composition mainly composed of polyester resin A and polyester resin B shown below was mixed to obtain an adhesive composition.

Polyester resin A 95 parts by weight Polyester resin B 5 parts by weight Polyisocyanate compound 25 parts by weight (manufactured by Nippon Polyurethane Co., Ltd., trade name Coronate C-2516) Hydrophobic silica 25 parts by weight (manufactured by Nippon Silica Co., Ltd., trade name Nip Seal 5Ssoll) Ethyleneimine System crosslinking agent 1 part by weight (manufactured by Shiraki Shokubai Kagaku Co., Ltd., trade name TAZ) Silane coupling agent 1 part by weight (manufactured by Nippon Unicar Co., Ltd., trade name Epoxysilane A-187) Toluene 150 parts by weight Methyl ethyl ketone 150 parts Comparative example 1 This example is an example in which no hydrophobic silica was added.

First, 25 mol% of neopentyl glycol, 25 mol% of ethylene glycol, and 25 mol% of terephthalic acid.

and 25 mol% of isophthalic acid were reacted to synthesize polyester resin A having a glass transition temperature of 65°C.

Then, a composition mainly composed of polyester resin A shown below was mixed to obtain an adhesive composition.

Polyester resin A 100 parts by weight Polyisocyanate compound 5 parts by weight (manufactured by Nippon Polyurethane Co., Ltd., trade name Millionate MR) Ethyleneimine crosslinking agent 1 part by weight (manufactured by Nippon Shokubai Kagaku Co., Ltd., trade name TAZ) Toluene 150 parts by weight Methyl ethyl ketone 150 parts by weight Comparison Example 2 This example uses untreated silica whose surface has not been subjected to hydrophobic treatment.

First, 25 mol% of neopentyl glycol, 25 mol% of ethylene glycol, and 25 mol% of terephthalic acid.

and 25 mol% of isophthalic acid were reacted to synthesize polyester resin A having a glass transition temperature of 65°C.

On the other hand, neopentyl glycol 50 mol%, dimethyl terephthalate 15 mol%, dimethyl isophthalate 15
Polyester resin B having a glass transition temperature of 5° C. was synthesized by reacting mol % and 20 mol % of succinic anhydride.

Then, a composition mainly composed of polyester resin A and polyester resin B shown below was mixed to obtain an adhesive composition.

Polyester resin A 95 parts by weight Polyester resin 8 5 parts by weight Polyisocyanate compound 5 parts by weight (manufactured by Nippon Boriurekun Co., Ltd., trade name Coronate C-2516) Untreated silica 25 parts by weight (manufactured by Nippon Silica Co., Ltd., trade name Nip Seal E-200- (No treatment) Ethyleneimine crosslinking agent 1 part by weight (manufactured by Nippon Shokubai Kagaku Co., Ltd., trade name TAZ) Silane coupling agent 1 part by weight (manufactured by Nippon Unicar Co., Ltd., trade name Epoxysilane^-187) Toluene 150 parts by weight Methyl ethyl ketone 150 parts by weight Comparative Example 3 This example is an example in which the amount of hydrophobic silica added exceeds 50% by weight.

First, 25 mol% of neopentyl glycol, 25 mol% of ethylene glycol, and 25 mol% of terephthalic acid.

and 25 mol% of isophthalic acid were reacted to synthesize polyester resin A having a glass transition temperature of 65°C.

Then, a composition mainly composed of polyester resin A shown below was mixed to obtain an adhesive composition.

Polyester resin A 100 parts by weight Polyisocyanate compound 15 parts by weight (manufactured by Nippon Polyurethane Co., Ltd., 5 trade name Millionate MR) Hydrophobic silica 120 parts by weight (manufactured by Nippon Silica Co., Ltd., trade name Nip Seal 5s50A) Ethyleneimine crosslinking agent Single plate part ( Manufactured by Nippon Shokubai Kagaku Co., Ltd., trade name TAZ) Silane coupling agent 1 part by weight (manufactured by Nippon Unicar Co., Ltd., trade name Epoxysilane A-187)
Toluene: 400 parts by weight Methyl ethyl ketone: 400 parts by weight Comparative Example 4 In this example, the glass transition temperature of the polyester resin exceeded 80°C.

First, 15 mol% of neopentyl glycol, 20 mol% of hydrogenated bisphenol A, 15 mol% of 1,4-cyclohexane dimetatool, 25 mol% of dimethyl terephthalate and 25 mol% of dimethyl isophthalate were reacted to form a mixture with a glass transition temperature of 85°C. Polyester resin C was synthesized.

Then, a composition mainly composed of polyester resin C shown below was mixed to obtain an adhesive composition.

Polyester resin 0 100 parts by weight Polyisocyanate compound 10 parts by weight (Nippon Polyurethane Co., Ltd., Coronate C-2516) Hydrophobic silica 25 parts by weight (Nippon Silica Co., Ltd., trade name Nip Seal 5S50A) Ethyleneimine crosslinking agent 1 part by weight (Nippon Shokubai Co., Ltd.) (Manufactured by Kagaku Co., Ltd., trade name TAZ) Silane coupling agent 1 part IN (manufactured by Nippon Unicar Co., Ltd., trade name Epoxysilane A-187) Toluene 150 parts by weight Methyl ethyl ketone 150 parts by weight Comparative Example 5 In this example, the glass transition temperature of the polyester resin was 50 This is an example of a temperature below °C.

First, 25 mol% of propylene glycol, 15 mol% of 1.4-cyclohexane dimetatool, 35 mol% of propylene glycol, 15 mol% of dimethyl terephthalate, and 25 mol% of dimethyl isophthalate were reacted to form a polyester resin with a glass transition temperature of 35°C. was synthesized.

Then, a composition mainly composed of a polyester resin shown below was mixed to obtain an adhesive composition.

Polyester resin D 100 parts by weight Polyisocyanate compound 5 parts by weight (manufactured by Nippon Polyurethane Co., Ltd., trade name Millionate MR) Ethyleneimine crosslinking agent 1 part by weight (manufactured by Nippon Shokubai Kagaku Co., Ltd., trade name TAZ) Toluene 150 parts by weight Methyl ethyl ketone 150 parts by weight Comparison Example 6 This example is an example in which no polyisocyanate compound was added.

First, 25 mol% of neopentyl glycol, 25 mol% of ethylene glycol, and 25 mol% of terephthalic acid.

and 25 mol% of isophthalic acid were reacted to synthesize polyester resin A having a glass transition temperature of 65°C.

Then, a composition mainly composed of polyester resin A shown below was mixed to obtain an adhesive composition.

Polyester resin A 100 parts by weight Hydrophobic silica '25 parts (manufactured by Nippon Silica Co., Ltd., trade name Nip Seal E20OA - methyltriethoxysilane treatment) Ethyleneimine crosslinking agent 1 part by weight (manufactured by Nippon Shokubai Kagaku Co., Ltd., trade name TAZ) Toluene iso parts by weight Methyl ethyl ketone 150ffi 1 part Above Example 1. The adhesive performance of each adhesive composition obtained in Example 2 and Comparative Examples 1 to 6 was investigated.

Sample Preparation Method First, the surface of a cold-rolled steel plate with a thickness of 0.5 ffll11 was degreased and cleaned, and then immersed in a 1% aqueous chromic acid anhydride solution for 10 seconds, washed with water, and dried. Then, the adhesive compositions obtained in the above Examples and Comparative Examples were applied onto the steel plate treated as described above so that the coating thickness was about 4 μm, and dried at room temperature. Next, heat the plate for 60 seconds at a final plate temperature of 180°C with an electrical open circuit.
Immediately, a semi-rigid vinyl chloride film was laminated using a laminator set at a linear pressure of 10 kg/c+* to produce each sample plate.

The initial peel strength and the peel strength after 2 hours of the spring water test were measured for each sample board produced as described above using the following method. The test method is as follows.

Initial peel strength: One hour after adhering the vinyl chloride film and the steel plate with the adhesive composition, 180 degree peeling was performed at a rate of 50 mg/min at 20°C, 65% relative humidity, and the strength was peeled from the steel plate. The resistance force when the vinyl chloride film peels off was determined.

Peel strength after 2 hours of clean water test: After each sample plate was immersed in boiling water for 2 hours, 180 degree peeling was performed at a speed of 50 mm per minute at 20°C and 65% relative humidity to remove chloride from the steel plate. The resistance force when the vinyl film peels off was determined.

The measurement results are shown in Table 1.

From the above results in Table 1, it is clear that an adhesive composition in which hydrophobic silica is added to a polyester resin with a glass transition temperature in the range of 50 to 80°C is capable of low-temperature adhesion and also shows good adhesion even after the fresh water test. It can be seen that it shows gender. In comparison, the glass transition temperature of polyester resin is 50-80°
If C is outside the range or if hydrophobic silica is not added, the adhesion will deteriorate after the fresh water test, especially in cases where the glass transition temperature of the polyester resin exceeds 80°C (Comparative Example 4). In an example in which the amount of hydrophobic silica is too large (Comparative Example 3), adhesion cannot be ensured even in the initial stage.

Furthermore, as shown in Comparative Example 6, the presence or absence of addition of polyisocyanate has a great influence on the adhesiveness, and it can be seen that in the case of no addition, the adhesiveness deteriorates.

Examples 3 to 5. Comparative Example 7 Next, various adhesive compositions were prepared by changing the amount of the polyisocyanate compound added, and the initial peel strength and the peel strength after 2 hours of the spring water test were similarly measured. The compositions of the prepared adhesive compositions (Examples 3 to 5 and Comparative Example 7) are shown in Table 2. In each of these adhesive compositions, the polyester resin used was the aforementioned polyester resin A.
The polyisocyanate compound was manufactured by Nippon Polyurethane Co., Ltd. under the trade name Coronate C-2516 or Millionate MR, and the hydrophobic silica was manufactured by Nippon Silica Co., Ltd.

The product name Nip Seal 5S50A was used as the ethyleneimine crosslinking agent, the product name TAZ (ω-aziridinylpropionic acid-2,2-dihydroxylmethyl-butanol ester) manufactured by Nippon Shokubai Kagaku Co., Ltd. was used as the ethyleneimine crosslinking agent, and the silane coupling agent was used as the silane coupling agent. Manufactured by Nippon Unicar Co., Ltd., trade name: Epoxysilane A-
187 were used, respectively.

(The following is a blank space) Table 3 shows the measurement results of the initial peel strength and the peel strength after 02 hours of the boiling water test.

Table 3 From the above results, the polyisocyanate compound is 10 to 50
It can be seen that when the weight % range is within the range, good adhesive strength is exhibited after the initial 5 boiling water tests.

Polyisocyanate compound is 50% by weight or more (Comparative Example 7
), the peel strength after the fresh water test decreases significantly due to the influence of unreacted polyisocyanate compounds.

〔Effect of the invention〕

As is clear from the above explanation, since the adhesive composition of the present invention uses a polyester resin with a glass transition temperature of 50 to 80°C, low ifl adhesion is possible, such as It is possible to maintain the appearance and commercial value of the vinyl chloride film without damaging its appearance. Note that the glass transition temperature can be controlled by changing the combination and synthesis ratio of the polyhydric alcohol and polybasic acid used when synthesizing the polyester resin, making it possible to synthesize a polyester resin with a predetermined glass transition temperature. .

In addition, in the present invention, hydrophobic silica is added to the polyester resin having the above-mentioned predetermined glass transition temperature, so the hydrophobicity of the adhesive is improved and adhesiveness can be ensured even after the fresh water test. , the water resistance can be significantly improved, and at the same time, since a predetermined amount of polyisocyanate compound is added, the adhesive properties of the adhesive composition are improved,
It is possible to significantly improve peel strength.

Therefore, according to the present invention, it is possible to provide an adhesive composition that is capable of low-temperature adhesion, has high peel strength, and is excellent in water resistance and adhesion properties.

Patent applicant: Sony Chemical Corporation Agent: Patent attorney: Akira Koike Same material Sakae Procedural amendment cap button June 15, 1986

Claims (1)

[Claims] An adhesive composition comprising 50% by weight or more of a polyester resin having a glass transition temperature T_G of 50 to 80°C, 5 to 50% by weight of hydrophobic silica, and 0.1 to 50% by weight of a polyisocyanate compound.