JPH0813957B2 - Aqueous adhesive composition - Google Patents

Description

TECHNICAL FIELD OF THE INVENTION The present invention relates to a novel aqueous pressure-sensitive adhesive composition for soft vinyl chloride in which adhesive properties such as adhesive strength and tack do not change with time.

2. Description of the Related Art Conventional techniques and their problems The pressure-sensitive adhesive is usually applied to paper, plastic film, etc. and applied to tapes, sheets, labels, etc. Aqueous emulsion-type pressure-sensitive adhesives have various advantages compared to organic solvent-type pressure-sensitive adhesives, such as no air pollution, excellent safety and health, and suitability for resource saving. From water to an aqueous emulsion type. Thus, water-based emulsion type adhesives have been used in various applications, but recently, solvent-based rubber type adhesives have been mainly used for soft insulation such as electrical insulation, wire binding, and miscellaneous goods. The development of water-based emulsion type pressure-sensitive adhesives is also desired for pressure-sensitive adhesives applied to tapes, sheets, labels and the like having vinyl as a support.

Conventionally, water-based emulsion type adhesives generally include acrylic emulsion type adhesives, styrene-butadiene copolymer latex (hereinafter referred to as SBR latex), natural rubber latex (hereinafter referred to as NR latex) as a base polymer, rosin and Glycerin ester of leveled rosin, terpene resin, a latex-based pressure-sensitive adhesive obtained by adding a tackifier resin emulsion such as petroleum resin is known, and a paper, polyester film, a pressure-sensitive adhesive tape using cellophane as a support, It is useful for labels and sheets. However, these conventional aqueous emulsion type pressure-sensitive adhesive tapes, sheets, and soft vinyl chloride as a support,
When used for labels etc., the adhesive strength immediately after production, tackiness such as tack is excellent, but the plasticizer due to the soft vinyl chloride support migrates from the soft vinyl chloride side to the adhesive layer over time. Therefore, there arises a problem that the adhesive strength of the pressure-sensitive adhesive and the pressure-sensitive adhesive property such as tack are remarkably lowered. Therefore, an aqueous emulsion type pressure-sensitive adhesive which can be used for tapes, sheets, labels and the like using soft vinyl chloride as a support has not yet been obtained.

Means for Solving the Problems The inventors of the present invention have the above problems of the conventional water-based emulsion type adhesives, that is, the water-based emulsion type adhesives to tapes, sheets, labels and the like having soft vinyl chloride as a support. As a result of intensive studies to solve the problem that the adhesive property significantly deteriorates with time when used, a mixture of SBR latices and NR latices in a specific ratio is used as a base polymer, and a specific tackifier resin is used. It was found that when a high softening point tackifier resin emulsion was used, the adhesive properties immediately after production did not deteriorate with time even when used in tapes, sheets, labels, etc. with soft vinyl chloride as a support. The invention was completed.

That is, the present invention provides a pressure-sensitive adhesive composition comprising a base polymer and a tackifier, wherein (1) the base polymer is a mixture of styrene / butadiene copolymer latex and natural rubber latex, and the former: the latter compounding ratio is solid. 80:20 in terms of weight ratio
50:50, and (2) the tackifier is a pentaerythritol ester of partially maleated disproportionated rosin and / or a pentaerythritol ester of partially fumarized disproportionated rosin,
Further, the present invention relates to a water-based pressure-sensitive adhesive composition for soft vinyl chloride, which is a resin emulsion in which a resin having a softening point of 110 to 140 ° C. is used as a substance to be dispersed.

In the present invention, a mixture of SBR latex and NR latex in a specific ratio is used as the base polymer.

Here, the SBR latex refers to SBR latex and / or carboxy-modified SBR latex, and those commercially available for pressure-sensitive adhesives can be usually used. The SBR latex preferably has a styrene / butadiene bond ratio of 25/75 to 45/55 in weight ratio in consideration of imparting rubber elasticity and low temperature physical properties. When the styrene content is 25 parts by weight, the glass transition point (hereinafter referred to as Tg) is lowered, so that sufficient cohesive force cannot be obtained. If it exceeds 45 parts by weight, the Tg becomes high and the tackiness decreases. Also, the gel fraction (toluene-insoluble matter weight%) is preferably 35 to 65%.
When it is less than 35%, the cohesive force is low. If it exceeds 65%, sufficient tack cannot be obtained. The modification ratio of the carboxy-modified SBR latex is generally 0.5 to 7% by weight. S
One kind of BR latex and carboxy modified SBR latex can be used, or two or more kinds having different bound styrene amount, gel fraction and carboxy modification rate can be used in combination at any ratio. Examples of commercially available products include, for example, carboxy-modified SBR latex with "PL-208" manufactured by Policer,
Examples include “PL-222”.

Further, as the NR latex, any of those used in this type of composition can be used, and both depolymerized and non-depolymerized ones may be used, but when the vinyl chloride tape or the like is used, cohesive force, cost, etc. Considering it, it is better not to depolymerize.

The mixing ratio of SBR latex and NR latex is 80:20 to 50:50 in terms of solid content weight ratio. It is preferably from 70:30 to 60:40, and more preferably, the amount of bound styrene in the mixture of SBR latex and NR latex is 20 to 32%. If the amount of bound styrene in SBR latex is small, lower the blending ratio with NR latex and
When the amount of bound styrene in R-latex is large, the compounding ratio of NR-latex may be increased. When the amount of styrene is small, the adhesive strength is lowered, and when it is too large, the plasticizer is remarkably transferred and the cohesive force is lowered.

On the other hand, as the tackifier resin used in the resin emulsion as one component in the composition of the present invention, one or two of pentaerythritol ester of partially maleated disproportionated rosin and pentaerythritol ester of partially fumarized disproportionated rosin are used. Must be a mixture of the above. That is, the object of the present invention is achieved by using the above tackifier resin.

Here, the pentaerythritol ester of partially maleated disproportionated rosin and the pentaerythritol ester of partially fumarized disproportionated rosin are obtained by the following methods. That is, at least one of maleic anhydride, maleic acid, and fumaric acid is added to 100 parts by weight of at least one of tall oil rosin, utudrosine, and gum rosin, and 1 to 5 parts by weight of the disproportionation catalyst is added. Disproportionate in the presence. Furthermore, in the presence or absence of an esterification catalyst such as methanesulfonic acid, pentaerythritol 8 to 15 is added to 100 parts by weight of the partially maleated disproportionated rosin and / or partially fumarized disproportionated rosin obtained above. It is obtained by subjecting parts by weight to an esterification reaction. The disproportionation reaction and the esterification reaction can be carried out in this order, in reverse order, or simultaneously. At this time, if the amount of at least one of maleic anhydride, maleic acid and fumaric acid used is less than 1 part by weight, the softening point tends to be insufficient, and if it is more than 5 parts by weight, the softening point tends to be high. It is not preferable because it tends to be too much and the compatibility tends to decrease. The softening point of the tackifier resin thus obtained is preferably 110 to 140 ° C, particularly preferably 120 to 130 ° C. Softening point is 110
If the temperature is less than ℃, the rate of decrease in adhesive strength with time is large.
If the temperature exceeds 140 ° C, the tack will be low.

Then, the resin is emulsified. As the emulsifier used at this time, α-olefin sulfone compound,
Alkyl sulphate, alkyl phenyl sulphate, polyoxyethylene alkyl phenyl ether sulphate, polyoxyethylene aralkyl phenyl ether half ester salt of sulfosuccinic acid, anionic emulsifier such as rosin soap, polyoxyethylene alkyl phenyl ether Nonionic emulsifiers such as The amount of the emulsifier is not particularly limited, but is usually about 1 to 10 parts by weight, preferably 1 to 5 parts by weight in terms of solid content, relative to 100 parts by weight of the resin. If it exceeds 10 parts by weight, the water resistance and adhesive strength of the pressure-sensitive adhesive will be reduced. If the amount is less than 1 part by weight, the stability of the resin emulsion becomes poor.

As a method for obtaining a high softening point tackifier resin emulsion, the high softening point tackifier resin is dissolved in a solvent such as benzene or toluene, and then the emulsifier and soft water are added,
Method of removing the solvent under reduced pressure after emulsification using a high-pressure emulsifier, mixing a small amount of solvent such as benzene and toluene so that the softening point of the resin is about 90 ° C or less, kneading the emulsifier, and further heating Water is gradually added to obtain an emulsion by phase inversion emulsification and then the solvent is removed under reduced pressure or used as it is, or the temperature is raised above the softening point of the resin in the autoclave and the emulsifier is kneaded and heat is applied. A method in which water is gradually added to cause phase inversion emulsification to emulsify, and the like can be mentioned, and any of these methods may be used.

The aqueous pressure-sensitive adhesive composition of the present invention is a base polymer
It is preferable to mix and use the mixture of the SBR latex and the NR latex and the tackifier in the range of 80:20 to 50:50 in terms of solid content. 70: 3 is particularly preferred
0 to 50:50. If the addition amount of the high softening point tackifier resin emulsion is less than 20 parts by weight, sufficient tackiness cannot be imparted, and if it exceeds 50 parts by weight, the cohesive force is remarkably reduced, which is not preferable. .

If desired, the aqueous pressure-sensitive adhesive composition of the present invention may contain a small amount of a defoaming agent, a thickener, a filler, an antioxidant, a water-proofing agent, a film-forming aid and the like.

EFFECTS OF THE INVENTION The water-based pressure-sensitive adhesive composition of the present invention can be suitably applied to tapes, sheets, labels, etc. having soft vinyl chloride as a support, which is used for electrical insulation, electric wire bundling, miscellaneous goods, etc., immediately after production. Adhesive strength, tackiness, and other tackiness characteristics do not deteriorate even after a lapse of days.

EXAMPLES Hereinafter, the present invention will be described in detail with reference to production examples, examples and comparative examples, but the present invention is not limited to these examples. In the examples, all parts and% are by weight unless otherwise specified.

Production Example Partially fumarized disproportionated rosin pentaerythritol ester (fumarization rate: 3.5% by weight, softening point 125 ° C) 100 parts was dissolved in toluene 60 parts at 100 ° C for about 1 hour, and then cooled to 80 ° C. Then, 3 parts of an anionic emulsifier (sodium salt of dodecylbenzene sulfonic acid) in terms of solid content and 160 parts of water were added, and the mixture was vigorously stirred at 75 ° C. for 1 hour for preliminary emulsification. The obtained preliminary emulsion was subjected to high pressure emulsification at a pressure of 300 kg / cm ² with a high pressure emulsifying machine (manton gaurin company) to obtain an emulsion. Next, 200 parts of the emulsion was charged into a vacuum distillation apparatus, and the temperature was adjusted to 50 ° C., 1
Distillation under reduced pressure for 6 hours under the condition of 00 mmHg gave 123 parts of pentaerythritol ester resin emulsion (50% solid content) of partially fumarized disproportionated rosin.

Example 1 30 parts of pentaerythritol ester resin emulsion of the partially fumarized disproportionated rosin obtained in Production Example (solid content conversion) and carboxy-modified SBR latex (“P
L-222 ", combined water lily content 42%, nonvolatile content 52%) 49 parts (solid content conversion), NR Latex (nonvolatile content 62%) 21 parts (solid content conversion), and further acrylic thickener As an amount, 0.5 part (solid content) of "Primal ASE-60" (manufactured by Nippon Acrylic Company, used by diluting nonvolatile content 28% to 5%) was added to obtain an aqueous pressure-sensitive adhesive composition.

Example 2 40 parts (solid content) of pentaerythritol ester resin emulsion of partially fumarized disproportionated rosin obtained in Production Example and carboxy-modified SBR latex (“P
L-222), bound styrene amount 42%, nonvolatile content 52%) 36 parts (solid content conversion), NR Latex (nonvolatile content 62%) 24 parts (solid content conversion), and further acrylic thickener As an amount, 0.5 part (solid content) of "Primal ASE-60" (manufactured by Nippon Acrylic Company, used by diluting nonvolatile content 28% to 5%) was added to obtain an aqueous pressure-sensitive adhesive composition.

Example 3 In the production example, the pentaerythritol ester of the partially maleated disproportionated rosin (maleated rate 1.5) was used in place of the pentaerythritol ester of partially fumarized disproportionated rosin (fumarization rate 3.5% by weight, softening point 125 ° C.). weight%,
Except that the softening point of 115 ° C.) was used, the same procedure as in Production Example was carried out to obtain an emulsion. Next, using this emulsion, an aqueous pressure-sensitive adhesive composition was obtained with the same composition as in Example 1.

Comparative Example 1 In the production example, the pentaerythritol ester of the partially fumarized disproportionated rosin was replaced with the glycerin ester of the disproportionated rosin (softening point 100 ° C., “super ester A-1
00 "manufactured by Arakawa Chemical Industry Co., Ltd. was used to obtain an emulsion by the same procedure as in the production example. Next, using this emulsion, an aqueous pressure-sensitive adhesive composition was obtained with the same composition as in Example 1.

Comparative Example 2 In the production example, a petroleum resin (softening point 100 was used instead of the pentaerythritol ester of the partially fumarized disproportionated rosin.
C., "Quinton D-100", manufactured by Nippon Zeon Co., Ltd. was used, and the same operation as in Production Example was carried out to obtain emulsion. Next, using this emulsion, an aqueous pressure-sensitive adhesive composition was obtained with the same composition as in Example 1.

Comparative Example 3 In the production example, a polyterpene resin (softening point 115 ° C., “YX-resin Px # 1150”, manufactured by Yasuhara Yushi Kagaku Kogyo Co., Ltd.) was used in place of the pentaerythritol ester of the partially fumarized disproportionated rosin. Otherwise, the same operation as in Production Example was carried out to obtain an emulsion. Next, using this emulsion, an aqueous pressure-sensitive adhesive composition was obtained with the same composition as in Example 1.

Comparative Example 4 In the production example, a pentaerythritol ester of a malenated rosin (softening point 150 ° C., “Marquide No. 5”, manufactured by Arakawa Chemical Industry Co., Ltd.) was used in place of the pentaerythritol ester of a partially fumarized disproportionated rosin. Except for using it, the same operation as in Production Example was performed to obtain an emulsion. Next, using this emulsion, an aqueous pressure-sensitive adhesive composition was obtained with the same composition as in Example 1.

Comparative Example 5 In the production example, a pentaerythritol ester of a polymerized rosin (softening point 121 ° C., “Pencel C”, manufactured by Arakawa Chemical Industry Co., Ltd.) was used in place of the pentaerythritol ester of a partially fumarized disproportionated rosin. In the same manner as in Production Example, the emulsion was obtained. Next, using this emulsion, an aqueous pressure-sensitive adhesive composition was obtained with the same composition as in Example 1.

How to make vinyl chloride tape "Hiker 1571C" (manufactured by BFGoodrich) / "PL-2" as a primer on soft vinyl chloride tape with a thickness of 150 μm
22 "= 1/1 (weight ratio) is applied so that the dry weight is ² to 3 g / m2, and then dried in a circulating air dryer at 70 ° C for 3 minutes,
It was left in a room at a temperature of 20 ° C and a relative humidity of 65% for 2 hours. Further, the aqueous pressure-sensitive adhesive composition was applied so that the weight after drying was 28 to 30 g / m ^2, and dried in an air-circulation dryer at 105 ° C. for 3 minutes and immediately wound up to prepare a vinyl chloride tape. . Then, the value measured after leaving it in a room at a temperature of 20 ° C. and a relative humidity of 65% for 24 hours was taken as the value immediately after the production. In addition, the vinyl chloride tape obtained above was left in a circulating air dryer at 70 ° C for 72 hours and then taken out, and after being left in a room at a temperature of 20 ° C and a relative humidity of 65% for 24 hours, the measured value was taken as the value after aging. did. The rate of change was calculated by the following formula.

Various tests are based on the following methods.

1. Adhesion: 180 ° at a measuring temperature of 20 ° C and a pulling speed of 300mm / min
The adhesive strength (g / cm) was measured by peeling. The adherend is a stainless plate.

2. Tuck: Measured by the J.Dow method described in JIS Z 0237 at a gradient of 30 ° and a measurement temperature of 20 ° C. The numbers in Table 1 are
Indicates Ball No.

3. Cohesive strength: The bonding area is 19 × 20 mm ² , the load is 1 kg, and the adhesive surfaces of the vinyl chloride tapes are shown as the holding time (minutes) at 20 ° C.

Claims (2)

[Claims] 1. A pressure-sensitive adhesive composition comprising a base polymer and a tackifier, wherein (1) the base polymer is a mixture of styrene / butadiene copolymer latex and natural rubber latex, and the former: the latter compounding ratio is solid. 80:20 in terms of weight ratio
50:50, and (2) the tackifier is a pentaerythritol ester of partially maleated disproportionated rosin and / or a pentaerythritol ester of partially fumarized disproportionated rosin,
A water-based pressure-sensitive adhesive composition for soft vinyl chloride, which is a resin emulsion comprising a resin having a softening point of 110 to 140 ° C. as a substance to be dispersed. 2. The aqueous pressure-sensitive adhesive composition according to claim 1, wherein the compounding ratio of the base polymer and the tackifier is 80:20 to 50:50 in terms of solid content.