JPS60179480A - Adhesive composition - Google Patents

Abstract

PURPOSE:To provide an adhesive compsn. which has no fear of causing a fire or any environmental pollution and is suitable for use in high-speed lamination work, by blending an aq. rosin emulsion type pressure-sensitive adhesive and a synthetic rubber latex with a chloroprene latex. CONSTITUTION:An adhesive compsn. is obtd. by blending 5-100pts.wt. (on a solid basis) aq. rosin emulsion type pressure-sensitive adhesive (A) (pref. an aq. emulsion of pentaerythritol ester-modified rosin having a softening point of as high as 110 deg.C) and 5-100pts.wt. (on a solid base; based on the combined quantity of component A and C) synthetic rubber latex (B) with 100pts.wt. (on a solid basis) chloroprene latex (C). Since the compsn. is in the form of an aq. emulsion, it has no fear of causing any environmental pollution or a fire by org. solvents and is suitable for use in bonding an inert adhered to a porous adhered or the inert adherends to each other, particularly in lamination bonding without detriment to coatability, particularly roll coater coating workability.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an aqueous emulsion type adhesive composition.

More specifically, by utilizing the extremely fast initial adhesive strength, durability, weather resistance, heat resistance, flame retardance, etc. of chloroprene latex as the basic resin properties, we have developed the tackiness and adhesion of rosin-based aqueous emulsion type adhesives. The present invention relates to an aqueous emulsion type adhesive composition for adhering inert adherends, such as plastic films, which utilizes the above and further blends synthetic rubber latex, and has particularly improved initial adhesion and adhesion.

Conventionally, for example, a film-like base material is made of inert adherends such as polyethylene, polypropylene, cellophane, vinyl chloride, polyester, etc., and one base material is paper,
As an adhesive for metal foil or the above inert base material,
Solvent-based adhesives and water-based or emulsion-based adhesives have been used.

The solvent-based adhesives mentioned above include urethane-based, polyester-based, synthetic rubber-based, natural rubber-based, and acrylic-based adhesives, and the water-based adhesives include vinyl acetate-vinyl acetate-acrylic copolymer. Emulsion adhesives such as , ethylene-vinyl acetate copolymers, synthetic rubber latex, acrylic adhesives, or adhesive adhesives such as these are used.

However, with solvent-based adhesives, organic solvents are scattered during work, which poses problems of occupational health in factories, fire hazards, and environmental pollution.Depending on the type of adherend, organic solvents may also cause contamination. There may be problems.

On the other hand, emulsion adhesives as water-based adhesives are advantageous in terms of occupational health, fire risk, environmental pollution, etc., but they take time to develop initial adhesive strength and do not adhere well to inert adherends. In addition, bonding using adhesives has problems in terms of contamination due to residual tack and insufficient adhesion.

Among this series of water-based adhesives, typical emulsion-based adhesives include chloroprene latex adhesives, but they have insufficient adhesion to inert adherends, such as various plastic films; If the adherend is porous, such as paper, sufficient adhesion cannot be obtained because of the lack of permeability thereto. The reason for this is thought to be that the particle size of chloroprene latex is larger than that of other emulsions such as synthetic rubber latex, that it has a large surface tension, and that it is crystalline.

As an adhesive that has improved on these drawbacks, there is an adhesive that is based on the above-mentioned chloroprene latex and contains a rosin-based aqueous emulsion type adhesive, but it still has insufficient adhesion to inert adherends and the initial adhesion is poor. There is no effect of improving adhesion due to penetration into porous adherends. Depending on the type of adhesive used, residual tack may cause a decrease in adhesive strength and coloration of the adhesive layer. Some organic solvents may be used. There are drawbacks such as being forced to do so, and improvements are required.

It is an object of the present invention to overcome the above-mentioned drawbacks and to bond inert and porous adherends or inert adherends to each other without impairing coating properties, especially roll coater coating properties. An object of the present invention is to provide an aqueous emulsion type adhesive composition which is suitable for use in lamination adhesives.

The inventors of the present invention have made extensive studies to achieve this objective, and have achieved this objective by combining a synthetic rubber latex with a blended composition of chloroprene latex and a rosin-based aqueous emulsion type adhesive.

That is, the present invention provides a chloroprene latex (1) with a solid content of 100 parts by weight, a rosin-based aqueous emulsion type adhesive (2) with a solid content of 5 to 100 parts by weight, and a total amount of (1) and O. This is an adhesive composition formed by blending synthetic rubber latex O with a solid content of 5 to 100 parts by weight.

The chloroprene latex used in the present invention includes:
For example, currently on the market, solid content 50-60, viscosity 1
0 to 500 cps, pI-17 to 12, one or more types of unmodified type or carboxyl group-modified type latex can be used, and any type can be used.

In addition, examples of rosin-based aqueous emulsion type adhesives that are currently on the market include solid content of 50% and viscosity of 5 to 200%.
Water-based emulsion type adhesives such as cps, pi-15 to 90 rosin glycerin ester, triethylene glycol ester, diethylene glycol ester, hagentaerythritol ester, etc. are mentioned, and particularly preferable ones are 110°C from the residual tack surface. Examples include aqueous emulsions obtained by modifying pentaerythritol esters of rosin having a high softening point as described above, and more preferably aqueous emulsions whose dry coating becomes colorless and transparent.

In the present invention, the rosin-based aqueous emulsion type adhesive (f) blending with adhesive X has a remarkable effect in improving the adhesion to the above-mentioned inert adherend, such as a polyester film.

The blending ratio of this rosin-based aqueous emulsion adhesive is as follows:
The solid content is in the range of 5 to 100 parts by weight, particularly preferably 30 to 80 parts by weight, based on 100 parts by weight of the solid content of the chloroprene latex.

When this value is less than 5 parts by weight, adhesion to inert adherends is lacking. If the amount exceeds 100 parts by weight, the initial adhesion caused by the uniform film-forming properties of the blended composition will be impaired;
Moreover, the IC also begins to lack water-resistant adhesion.

The synthetic rubber latex used in the present invention is preferably an adhesive type, with styrene, methyl methacrylate, or butadiene as the main monomer, and carboxyl group-containing unsaturated acid monomers such as acrylic acid, methacrylic acid, itaconic acid, maleic acid, Using crotonic acid etc., using 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, 2-hydroxyglobyl acrylate etc. as a hydroxyl monomer, and further using ethyl acrylate, phthyl tecrylate, 2-hydroxyl acrylate, 2-hydroxyglobyl acrylate, etc. as a tackifying monomer, that is, a soft monomer. Among ethylhexyl acrylate, 2-ethylhexyl acrylate and the like are copolymerized. On the other hand, as a molecular weight regulator (chain transfer agent), t-dodecylmerkafrine, 11-dodecylmerkafrine, tetrachloride powder, acid, etc. were used for emulsion polymerization, and the average particle size was 0.1 to 0.
．． 5μ, gel content when dissolved in toluene: 20 or less, glass transition temperature -30 to -50°C, preferably -45 to -
The copolymer itself is internally plasticized at 50°C and is a sticky synthetic rubber latex, and SBR latex is particularly preferred.

The most preferable composition ratios of the functional group monomer, soft monomer, and molecular weight modifier in the synthetic rubber latex described above are as follows. That is, the amount of the carboxyl group-containing unsaturated acid monomer as a functional group monomer is preferably in the range of 0.5 to 3.0% by weight based on 100% by weight of the total amount of copolymerized monomers, and if it is less than 0.5% by weight, the polymerization Stability,
There is a problem with adhesion, and if the amount exceeds 30% by weight, the viscosity of the polymerization system increases and a stable polymer cannot be obtained.

In addition, the amount of hydroxyl monomer as a functional group monomer is (1.3 to 3.0
A range of % by weight is preferable; if it is less than 0.5% by weight, there will be problems with polymerization stability and adhesion, and if it is more than 3.0% by weight, the latex particles will become unstable during polymerization, resulting in problems with stable polymerization. Can't get union.

The amount of soft monomer is preferably in the range of 2 to 15% by weight based on 100% by weight of the total amount of copolymerized monomers.If it is less than 2% by weight, the polymer will lack stickiness, and if it is more than 15% by weight, it will be sticky. This increases the polymerization stability, and at the same time, when used as an adhesive, the cohesive force decreases.

The amount of the molecular weight regulator is preferably in the range of 0.1 to 2.0% by weight based on 100% by weight of the total amount of copolymerized monomers. Large particles are generated, which impairs the adhesive composition's characteristic properties of penetration into adherends and adhesion, and the gel content is high, resulting in a lack of adhesiveness. On the other hand, if the amount is more than 2.0% by weight, the tackiness increases and the cohesive force when used as an adhesive decreases significantly.

Furthermore, factors that influence the particle size of synthetic rubber latex include the type and quantitative factors of the surfactant used during emulsion polymerization of the latex; From the viewpoint of emulsion polymerization rate, it is preferable to use an anionic surfactant such as sodium evadodecylbenzenesulfonate, and the amount is 0.2 to 0.5% by weight based on 100% by weight of the total amount of copolymer monomers. A range is preferred.

The composition ratio of this adhesive type synthetic rubber latex is in the range of 5 to 100 parts by weight, particularly preferably 20 to 60 parts by weight, based on the total amount of chloroprene latex and rosin-based aqueous emulsion type adhesive. This is the blending ratio.

The purpose of blending synthetic rubber latex in the present invention is to
As mentioned above, initial adhesion to inert adherends, adhesion,
It improves penetration adhesion to porous adherends, and if it is less than 5 parts by weight, it has little effect on initial adhesion, etc., and when a peel test is performed, it easily peels off from the interface of an inert adherend, making it impractical. It lacks. If the amount is more than 100 parts by weight, the adhesion to inert adherends and the permeability to porous adherends are significantly improved, but a film such as a skin on the roll coater of the applicator is formed too quickly. This problem arises, and especially in the case of an adhesion method using a roll coater method or the like, it lacks practicality.

Furthermore, in order to exhibit the performance of the adhesive composition of the present invention,
The following surfactants may be used in combination.

Preferred surfactants used include polyoxyethylene alkyl ether, holoxyethylene alkyl allyl ether, alkylnaphthalene sulfonate, dialkyl sulfosuccinate salt, acetylene glycol-alcohol, and ethylene oxide adduct of acetylene glycol. However, among these, those with excellent wettability (wettability) and permeability are preferable, and dialkyl sulfo-1-torosilic acid esters are particularly preferable for wet application to inert adherends such as polyester films. It is preferable to use

The amount of this surfactant added is 100% of the total amount of the adhesive composition.
The solid content is used in a range of 0.0 l-() to 5 parts by weight, and the addition amount is particularly preferably 0.03 to 0.1 parts by weight. If this value is less than 0.01, the wettability may not be perfect depending on the type of inert adherend;
If the number is higher than the number of times, it tends to reduce water resistance.
It also lacks practicality due to foaming problems.

The adhesive composition of the present invention may be used by adding various additives such as antifoaming agents, thickeners, thixotropic agents, antifreeze agents, antiaging agents, and coloring agents, if necessary. .

When using the adhesive composition of the present invention, it is usually used as a so-called molding adhesive in which each component is added and blended in advance, but it may also be used by blending each component at the time of use.

When applying such an adhesive, it is usually possible to apply the undiluted solution to an inert adherend using a roll coater or the like, but in some cases it may be used after diluting it slightly with water.

As mentioned above, since the adhesive composition of the present invention is an aqueous emulsion type, there are environmental problems due to organic solvents, fire danger, etc.
There is no need to worry about occupational health issues, and it has application suitability suitable for high-speed lamination processing and extremely quick initial adhesion development, as well as excellent adhesion to inert adherends and stain-resistant and water-resistant adhesion due to residual tack. It has excellent properties and has high practical value as an adhesive for the so-called lamination method, for example.

Next, the present invention will be specifically explained with reference to Examples and Comparative Examples, but the present invention is not limited to the following Examples. .

Example 1 To 100 parts of chloroprene latex (manufactured by Denki Kagaku Kogyo Co., Ltd., trade name L■-60, solid content 60), rosin-based aqueous emul/Yon type adhesive (manufactured by Kagaku Kogyo Co., Ltd., 72 parts of KE 709 (trade name, solid content 50%) and 50 parts of synthetic rubber latex (manufactured by Mitsui Toatsu Chemical Co., Ltd., trade name Structbond 1351, solid content 48%) were mixed,
The adhesive composition of the present invention was obtained by stirring and mixing.

This adhesive composition was used to laminate a film as shown below with paper under the following bonding conditions, and was subjected to various performance tests as described below.

The results are shown in Table-1.

(1) Specifications of the test film and paper (1-1) Polyester film (magnetic tape) (commercially available magnetic tape for cassettes) Film width: 6mm (shoulder), film thickness: 25μ (1-2) Paper thickness: 150μ high-quality paper (2) Adhesive conditions and various performance test conditions (2-1) Roll coater application characteristics Using a Kumagai Riki Gum Up Tester (roll coater), only the pickup roll was driven and 11 adhesive tanks were applied. was filled with adhesive and continuously rotated at 78 rpm for 72 hours, and the thickening, foaming, agglomeration, and skinning property on the roll were observed, and each of the above items was expressed as follows.

○... No abnormalities observed △... Some problems ×... Practical problems (2-2) Coating characteristics (repellent) Magnetic coating using a wire bar coater manufactured by Igu J610 on Kumagai Riki A 10μ thick adhesive was applied to the back side of the tape, and the presence or absence of wetting on the film was observed and indicated as shown below.

○...No repelling △...Some repelling phenomenon is observed ×... Repelling (2-3) In the same manner as initial adhesion (2-2), immediately bond the papers together after applying the adhesive. The adhesive layer was pressed back and forth once with a rubber roll weighing 1 kg, and after 5 seconds, the adhesive layer was peeled off with a fingertip and the adhesive state was observed and displayed as shown below.

○...Paper is completely broken ○...Paper is broken with a coefficient of 50 or less △...Paper is broken with a coefficient of 10 or less ×...Peeling from the film interface (2-4) Normal adhesion (273) Observe the adhesion state after 1 hour in the same way as above.
Displayed in the same way.

(2-5) After applying in the same manner as residual tack (2-2), dry at room temperature for 1 hour, turn over the paper, place a 115 kg weight on top of it, pressurize it for 10 minutes, and see if the residual tack separates from the paper. The presence or absence of adhesion was observed and a comprehensive judgment was made using finger tack, as shown below (displayed).

○...Does not adhere to paper and has no finger tack ○...Does not adhere to paper but has some finger tack (tack, small) △...Slightly adheres to paper and has finger tack (tack) ,
Small) ×...Completely adheres to the paper and has tack to the touch (tack dog) (2-6) Water resistant adhesion (2-4,) 20 parts of the sample prepared in ) were immersed in water at 2°C. The adhesive strength immediately after being taken out after 30 minutes was tested in the same manner as in (2-3) and displayed in the same manner.

Example 2 100 parts of chloroprene latex (manufactured by Denki Kagaku Kogyo Co., Ltd., product name LA-50, solid content 50%) and KE-709,60 as a rosin-based aqueous emulsion adhesive.
Structbond 135 as part and synthetic rubber latex
1 was blended and stirred to obtain an adhesive composition of the present invention.

The test was conducted in the same manner as in Example 1, and the results are shown in Table 1.

Example 3 100 parts of chloroprene latex (manufactured by Showa Neoprene Co., Ltd., trade name 115, solid content 47%), 56 parts of KE-709 as a rosin-based aqueous emulsion type adhesive, and Structbond 1351 as synthetic rubber latex.
．． 40 parts were mixed and stirred to obtain an adhesive composition of the present invention.

The test was conducted in the same manner as in Example 1, and the results are shown in Table 1.

Example 4 100 parts of LV-60 as chloroprene latex and KE-709 as a rosin-based aqueous emulsion type adhesive
, 72 parts and 1351.6 parts of Structbond as synthetic rubber latex were mixed with stirring to obtain an adhesive composition of the present invention.

The test was conducted in the same manner as in Example 1, and the results are shown in Table 1.

Example 5 100 parts of LV-60 as chloroprene latex and KE-70 as rosin-based aqueous emulsion type adhesive
9.72 parts of the adhesive composition and 1351.200 parts of Structbond as synthetic rubber latex were mixed and stirred to obtain an adhesive composition of the present invention.

The test was conducted in the same manner as in Example 1, and the results are shown in Table 1.

Example 6 100 parts of LV-60 as chloroprene latex and KE-709 as a rosin-based aqueous emulsion type adhesive
, 6 parts and Structobond 1 as synthetic rubber latex
351.50 parts were mixed and stirred to obtain an adhesive composition of the present invention.

The test was conducted in the same manner as in Example 1, and the results are shown in Table 1.

Example 7 100 parts of LV-60 as chloroprene latex and 1 g of rosin-based aqueous emulsion type adhesive E-709.1
20 parts and Structobond 1 as synthetic rubber latex
351.50 parts were mixed and stirred to obtain an adhesive composition of the present invention.

The test was conducted in the same manner as in Example 1, and the results are shown in Table 1.

Comparative Example 1 A test was conducted in the same manner as in Example 1 using a chloroprene latex obtained by removing the adhesive synthetic rubber latex from the composition used in Example 1 and a rosin-based aqueous emulsion adhesive composition. Shown in 1.

Comparative Example 2 Using only the chloroprene latex used in Example 1,
The test was carried out in the same manner as in Example ①, and the results are shown in Table 1.

Comparative Example 3 A test was conducted in the same manner as in Example 1 using only the rosin-based aqueous emulsion adhesive used in Example 1, and the results are shown in Table 1.

Comparative Example 4 A test was conducted in the same manner as in Example 1 using only the adhesive type synthetic rubber latex used in Example 1, and the results are shown in Table 1.

Comparative Example 5 A test was conducted in the same manner as in Example 1 using a composition containing chloroprene latex and adhesive synthetic rubber latex obtained by removing the rosin-based aqueous emulsion type adhesive from the composition used in Example 1. The results are shown in Table 1. It was shown to.

Reference Example 1 100 parts of LV-60 as chloroprene latex and KE-709 as rosin-based aqueous emulsion type adhesive
, 72 parts and general carboxyl group-modified synthetic rubber latex (manufactured by Mitsui Toatsu Chemical Guni, trade name Structbond 1051, solid content 48%, average particle size 0.2μ, gel content when dissolved in toluene 95% or more, glass) Transition temperature -
A blended composition obtained by blending and stirring and mixing 50 parts (25°C) was tested in the same manner as in Example 1, and the results are shown in Table 1.

Reference Example 2 A rosin-based aqueous emulsion type adhesive (Department Chemical Industry 1) was added to 100 parts of LV-60 as chloroprene latex.
, product name 5E-50, solid content 50 t, softening point 75
C) and 1,351.50 parts of Structbond as a synthetic rubber latex, and mixed with stirring, a blended composition was tested in the same manner as in Example 1, and the results are shown in Table 1.

Claims (1)

[Claims] Chloroprene latex (1) with a solid content of 100 parts by weight, a rosin-based aqueous emulsion type adhesive 0 with a solid content of 5 to 100 parts by weight relative to the solid content, and a solid content of 5 to 100 parts by weight relative to the total amount of the solid content of (1) and O. An adhesive composition made of a synthetic rubber latex.