JP2548033B2 - Rosin derivative, production method thereof, hot melt adhesive composition and production method thereof - Google Patents

Description

TECHNICAL FIELD The present invention relates to a hot melt adhesive composition, and more particularly to a polystyrene-polyisoprene-polystyrene block copolymer (SIS) or a polystyrene-polybutadiene-polystyrene block copolymer. The present invention relates to an improvement in tackifying resin in a pressure-sensitive hot melt adhesive composition comprising a block rubber such as a polymer (SBS), a rosin-based tackifying resin and a plasticizer.

The hot-melt adhesive is solid at room temperature and melts by heating to form a liquid, which is applied to various base materials for bonding. Then, by cooling, it solidifies again to develop an adhesive force.

Therefore, especially the block rubber hot melt adhesive is
It has a high degree of adhesiveness even when it is cooled and solidified, and is used as a pressure-sensitive adhesive.

2. Description of the Related Art Conventionally, as pressure-sensitive adhesives, rubber-based polymeric substances such as natural rubber, styrene-butadiene rubber, and acrylic resin have been generally compounded with a tackifying resin and a plasticizer, and further, an antioxidant and an antioxidant. It is known that an agent, a filler, a coloring agent and the like are appropriately mixed. Then, this was applied in the form of a solution or emulsion to a substrate such as paper or cloth, dried, and used as an adhesive tape, a label or the like.

However, in recent years, from the standpoints of environmental protection, resource saving, and improvement of productivity, hot-melt pressure-sensitive adhesives that use so-called block rubber as a base polymer have been widely used instead of those that use solvents and dispersants. It is supposed to be done.

Generally, this type of hot-melt pressure-sensitive adhesive is mainly composed of a block rubber, a tackifying resin, and a plasticizer, and tackifies 100 parts by weight of the block rubber. It is composed of 70 to 150 parts by weight of resin and 20 to 30 parts by weight of plasticizer. As the tackifying resin, a rosin-based resin excellent in aging resistance and heat stability is widely used.

Furthermore, as an improved version of this rosin-based tackifying resin, the hot melt adhesive composition described in JP-A-60-20977 is known. This hot melt adhesive composition uses a partially fumarized and / or partially maleated asymmetric asymmetric rosin ester as a tackifying resin. Thus, in the hot melt adhesive composition shown here, there is no migration of the plasticizer, the corrugated board sealing property is excellent, and the plasticizer does not penetrate into the base material of the label. ing.

Problems to be Solved by the Invention However, in the hot melt adhesive composition, the adhesive strength as a pressure-sensitive adhesive cannot be said to be sufficient, and particularly the adhesive strength to polyethylene is weak.

Originally, polyethylene is a non-polar material that is difficult to bond with any adhesive. The same applies to the hot melt adhesive composition, and the advent of an adhesive capable of strongly adhering to polyethylene is desired.

The present invention has been made in view of such circumstances, and an object thereof is to provide a hot-melt adhesive composition having excellent adhesiveness, high adhesive strength, and particularly excellent adhesiveness to polyethylene. is there.

Another object of the present invention is to provide a novel rosin derivative having a use as a tackifier in the above hot melt adhesive composition.

Means for Solving the Problems Thus, the rosin derivative of the present invention is a polyhydric alcohol ester of an asymmetric asymmetric rosin partially added with acrylic acid.

In this rosin derivative, the addition rate of acrylic acid to the above-mentioned asymmetrical rosin is preferably 2.3 to 45 mol%.

The invention of the method for producing the rosin derivative, the rosin, addition reaction of acrylic acid and asymmetric reaction,
After that, add polyhydric alcohol to the reaction product,
It is characterized in that the esterification reaction is carried out while dehydrating.

Next, the hot-melt adhesive composition of the present invention is a pressure-sensitive hot-melt adhesive composition containing a block rubber, a tackifying resin and a plasticizer as main components, wherein the tackifying resin partially adds acrylic acid. It is characterized by being a polyhydric alcohol ester of asymmetric asymmetric rosin.

In this hot melt adhesive composition, the block rubber is preferably a polystyrene-polyisoprene-polystyrene block copolymer or a polystyrene-polybutadiene-polystyrene block copolymer.

The rosin, which is a raw material of the tackifying resin in the hot melt adhesive composition, is preferably purified.

Further, in the hot melt adhesive composition, it is preferable that the addition rate of acrylic acid to the raw material rosin in the tackifying resin is 2.3 to 45 mol% and the softening point of the tackifying resin is 100 to 140 ° C.

Further, the invention of the method for producing the hot melt adhesive composition is such that an addition reaction of acrylic acid to rosin is carried out, and then a polyhydric alcohol is added to the acrylic acid addition product of the rosin to effect an esterification reaction while dehydrating. The rosin asymmetric reaction is carried out at any stage of these reactions, and the obtained rosin derivative is mixed with a block rubber and a plasticizer.

The rosin derivative of the present invention is a polyhydric alcohol ester of an asymmetric asymmetric rosin partially added with acrylic acid.
As the rosin as the raw material, gum rosin, wood rosin or tall oil rosin can be used.

Further, this rosin derivative can be obtained by adding acrylic acid to a raw material rosin, then asymmetrically making this, and then performing an esterification reaction with a polyhydric alcohol.

Acrylic acid is partially added to the raw material rosin, and the addition rate is preferably 2.3 to 45 mol% with respect to the raw material rosin. More preferably, it is about 4 to 25 mol%. When the addition rate of acrylic acid is low, the tackiness is excellent, but the adhesive strength is insufficient. On the other hand, if the addition rate is too high, the tackiness is poor and the compatibility with the block rubber is poor.

The addition reaction of acrylic acid to the raw material rosin can be performed by a known method. For example, by heating and melting the raw material rosin,
By adding acrylic acid to this, a Diels-Alder type addition reaction can be performed. Further, it may be carried out under pressure or under normal pressure.

The asymmetric reaction of rosin can also be performed by a known method. For example, it can be carried out by adding acrylic acid to the raw material rosin and then adding the asymmetric catalyst under heating and melting. As an asymmetric catalyst,
Examples thereof include noble metals such as palladium carbon, nickel and platinum, iodine compounds such as iodine and iron iodide, and sulfur compounds such as sulfur dioxide and iron sulfide.

The asymmetric reaction is 0.5% of conjugated dienoic acid in rosin.
It is preferable to carry out until the following. If the asymmetric reaction is insufficient, the heating stability is insufficient.

The asymmetric reaction may be performed at any stage of the reaction. That is, acrylic acid may be added to rosin that has been asymmetrical in advance, or an acrylic acid adduct of rosin may be asymmetrical. Furthermore, it is also possible to carry out asymmetry after the esterification reaction described below.

The polyhydric alcohol to be esterified with rosin in the present invention is preferably a trihydric or higher alcohol in consideration of the molecular weight, softening point and the like of the obtained rosin derivative. Specific examples include glycerin, diglycerin, pentaerythritol, dipentaerythritol, and the like, with glycerin or pentaerythritol being particularly preferred.

The esterification reaction is carried out on the raw material rosin to which at least acrylic acid has been added. This esterification reaction can be carried out in the same manner as the usual esterification reaction of rosin. That is, mixing rosin and alcohol,
The reaction can be performed while heating and melting while dehydrating, or by melting in a solvent and reacting while dehydrating in the presence of a suitable catalyst.

The ratio of rosin to alcohol in the esterification is
It is suitable that the hydroxyl group in the alcohol is about 1 equivalent to 1 equivalent of the carboxylic acid in the acrylic acid adduct of rosin.

The hot melt adhesive composition of the present invention is mainly composed of a block rubber, a tackifying resin, and a plasticizer.

The block rubber is a block copolymer in which a crystalline molecular chain is bound to both terminals of an amorphous molecular chain, and as a specific example thereof, polystyrene-polyisoprene-polystyrene block copolymer (SIS) or , Polystyrene-
Polybutadiene-polystyrene block copolymer (SB
S) and the like. Moreover, as those commercial products,
Shell Chemical Co., Ltd. Califlex TR-1107 (SIS)
Another example is Califlex TR-4113 (SBS).

The rosin derivative is used as the tackifying resin in this hot melt adhesive composition.

As the plasticizer blended in the hot melt adhesive composition, those conventionally used for this kind of adhesive composition can be used, for example, DOP, naphthenic mineral oil, polybutene, chlorinated. Biphenyl and the like can be mentioned.

In the hot melt adhesive composition of the present invention, the mixing ratio of the block rubber, the tackifying resin and the plasticizer is three.
Depending on the application and required characteristics of the adhesive composition, the block rubber may be added in an amount of 70 to 150 parts by weight and the plasticizer in an amount of 40 to 120 parts by weight, based on 100 parts by weight. Appropriate.

The hot melt adhesive composition of the present invention is produced by mixing the block rubber, the tackifying resin and the plasticizer. As a mixing means, an ordinary mixing roll or the like can be used. Then, the obtained hot-melt adhesive composition is heated and melted as it is, paper, cloth,
A pressure-sensitive adhesive sheet can be obtained by applying it to a substrate such as plastic.

Example Hereinafter, an example of the present invention will be described.

Preparation of Rosin Derivative Example 1 100 parts by weight of gum rosin was charged into a four-necked flask equipped with a stirrer, a drainage tube equipped with a cooling tube, a thermometer and a nitrogen injection tube, and heated to 180 ° C. under a nitrogen atmosphere to melt with stirring. Next, 1 part by weight of acrylic acid (4.6 mol% relative to rosin) was added dropwise at the same temperature, the temperature was raised to 200 ° C., and the acrylic acid addition reaction was carried out under reflux.

Further, 0.07 part by weight of palladium carbon (5% Pd-C) was added, the temperature was raised to 260 ° C, and the asymmetric reaction was carried out until the conjugated dienoic acid became 0.5% or less.

Then, after melting the catalyst to remove the catalyst, the product 10
0 part by weight and 11.1 part by weight of pentaerythritol were charged into the reaction apparatus, and esterification was carried out at 280 ° C. for 15 hours under a nitrogen stream to obtain a rosin derivative.

The softening point of this resin was 110 ° C., the acid value was 15.8, and the Gardner color tone was 7.

Example 7 The amount of acrylic acid added to gum rosin was 3.5 parts by weight (relative to rosin 16.1 mol%), the amount of pentaerythritol added was 12.3 parts by weight, and otherwise the same operation as in Example 1 to obtain a rosin derivative. It was

The softening point of this resin was 118 ° C., the acid value was 15.8, and the Gardner color tone was 7.5.

Example 3 The addition amount of acrylic acid to gum rosin was 4.9 parts by weight (22.6 mol% based on rosin), the addition amount of pentaerythritol was 13.0 parts by weight, and otherwise the same operation as in Example 1 was carried out to obtain a rosin derivative. It was

The softening point of this resin was 125 ° C, the acid value was 15.6, and the Gardner color tone was 7.5.

Example 4 A rosin derivative was obtained in the same manner as in Example 3 except that 11.8 parts by weight of glycerin was added instead of pentaerythritol in Example 3.

The softening point of this resin was 110 ° C., the acid value was 8.0, and the Gardner color tone was 6.

Example 5 A 2-volume distillation flask equipped with a thermometer and an air-cooled tube was charged with 1200 g of gum rosin and heated to 180 ° C. under a nitrogen atmosphere to completely dissolve the raw material gum rosin.
Cooled to ° C. Next, the system was depressurized to 3 mmHg, the temperature in the flask was raised to 280 ° C, and the system was distilled under reduced pressure to obtain 1130 g (yield 9
4.2%) of distilled rosin was obtained. The distillation residue was 3.8% and the loss was 2.0%.

The purified rosin obtained had a softening point of 76 ° C. and an acid value of 170.

In the operation of Example 1, the purified rosin was used instead of gum rosin, the addition amount of acrylic acid was 3 parts by weight (13.7 mol% relative to rosin), the addition amount of pentaerythritol was 12.3 parts by weight, and the others were The same procedure as in Example 1 was carried out to obtain a rosin derivative.

The softening point of this resin was 118 ° C., the acid value was 15.8, and the Gardner color tone was 6.

Example 6 The amount of acrylic acid added to the purified rosin was 4.9 parts by weight (based on rosin 22.6 mol%), the amount of pentaerythritol added was 11.8 parts by weight, and otherwise the same operation as in Example 5 was carried out to obtain a rosin derivative. Obtained.

The softening point of this resin was 126 ° C., the acid value was 15.5, and the Gardner color tone was 6.

Example 7 The same operation as in Example 6 was carried out except that glycerin was used instead of pentaerythritol as the polyhydric alcohol.
A rosin derivative was obtained.

The softening point of this resin was 112 ° C., the acid value was 7.0, and the Gardner color tone was 5.5.

Comparative Example 1 In the same manner as described in Example 1, 100 parts by weight of gum rosin was charged into a reactor and heated to 180 ° C. under a nitrogen atmosphere to melt with stirring. Then, 3.0 parts by weight of maleic anhydride (10.1 mol% with respect to rosin) was added, and the temperature was raised to 220 ° C. to carry out the maleation reaction.

Further, 0.07 part by weight of palladium carbon (5% Pd-C) was added, the temperature was raised to 280 ° C., and the asymmetric reaction was carried out until the conjugated dienoic acid became 0.5% or less.

After melting the catalyst to remove the catalyst, the product 10
0 part by weight and 11.9 parts by weight of pentaerythritol were charged into the reactor, and esterification was carried out at 280 ° C. for 15 hours under a nitrogen stream to obtain a rosin derivative.

The softening point of this resin was 110 ° C., the acid value was 15.8, and the Gardner color tone was 7.

Comparative Example 2 In place of maleic anhydride in Comparative Example 1, 2.5 parts by weight of fumaric acid (8.5 mol% based on rosin) was added, the amount of pentaerythritol added was 11.7 parts by weight, and the other operations were performed in the same manner as in Example 1. A rosin derivative was obtained.

The softening point of this resin was 118 ° C, the acid value was 15.8, and the Gardner color tone was 7 ⁺ .

Comparative Example 3 In the same manner as described in Example 1, 100 parts by weight of gum rosin was charged into a reaction apparatus, heated to 180 ° C. under a nitrogen atmosphere, and melted with stirring.

Then, without performing addition reaction of acrylic acid,
0.07 parts by weight of palladium carbon (5% Pd-C) was added, the temperature was raised to 280 ° C., and the asymmetric reaction was carried out until the conjugated dienoic acid became 0.5% or less.

Then, after melting the catalyst to remove the catalyst, 100 parts by weight of the asymmetrical rosin and 9.5 parts by weight of glycerin were charged into the reactor, and esterification was performed at 280 ° C for 15 hours under a nitrogen stream to obtain a rosin derivative. Obtained.

The softening point of this resin was 98 ° C., the acid value was 7.5, and the Gardner color tone was 8.

Comparative Example 4 A rosin derivative was obtained in the same manner as in Comparative Example 3 except that pentaerythritol was used instead of glycerin in the operation of Comparative Example 3.

The softening point of this resin was 105 ° C., the acid value was 15.4, and the Gardner color tone was 9.

Comparative Example 5 100 parts by weight of gum rosin was charged into the same reactor as described in Example 1, heated to 180 ° C. under a nitrogen atmosphere, and melted with stirring. Then 3.5 parts by weight of acrylic acid (vs. rosin 16.
(1 mol%) was added dropwise at the same temperature, the temperature was raised to 200 ° C., and the addition reaction of acrylic acid was carried out under reflux.

Then, without performing the asymmetric reaction on the product,
100 parts by weight of the product and 12.5 parts by weight of pentaerythritol were charged into the reaction apparatus, and esterification was carried out at 280 ° C. for 15 hours under a nitrogen stream to obtain a rosin derivative.

The softening point of this resin was 113 ° C., the acid value was 16.0, and the Gardner color tone was 8.

Comparative Example 6 100 parts by weight of 25% polymerized rosin (Polypar resin made by Rika Hercules Co., Ltd.) was charged into the same reactor as in Example 1, and heated at 180 ° C. under a nitrogen atmosphere to melt with stirring.
Next, 9.9 parts by weight of pentaerythritol was added, and esterification was carried out at 280 ° C for 15 hours under a nitrogen stream to obtain a rosin derivative.

The softening point of this resin was 120 ° C., the acid value was 15.5, and the Gardner color tone was 7.5.

Preparation of Hot Melt Adhesive Composition Using the rosin derivative obtained in each Example and Comparative Example as a tackifying resin, a hot melt adhesive composition was prepared with the following formulation.

SIS base SIS (trade name Califlex TR-1 manufactured by Shell Chemical Co., Ltd.
107) 100 parts by weight Tackifying resin (rosin derivative of each Example and Comparative Example) 10
0 parts by weight Naphthenic mineral oil (Shell Chemical Co., Ltd., trade name Shelf Rex 7-371) 50 parts by weight SBS base SBS (trade name Califlex TR-4113) 100 parts by weight Tackifying resin (same as above) 100 parts by weight Naphthenes 50 parts by weight of mineral oil (same as above) Test method About hot-melt adhesive composition using each rosin derivative obtained by each of the above Examples and Comparative Examples, a test piece obtained by applying this to a polyester film at 180 ° C The following performance tests were conducted using

Compatibility The transparency of the test piece was visually observed.

○: Transparently compatible.

Δ: A little turbidity and poor compatibility.

X: There is turbidity and they are incompatible.

Tackability J.Dow method rolls a steel ball of 1 to 32/32 inch with an inclination angle of 30 degrees, glue surface length of 10 cm, and running distance of 10 cm, and the maximum steel ball number that stops within the glue surface is obtained. displayed.

Peel strength The test piece was attached to a stainless steel plate (longitudinal polished with water-resistant abrasive paper # 280) and a polyethylene plate, and the 180-degree peel strength was measured at a tensile strength of 300 mm / min. For the stainless steel plate, the peel strength was measured immediately after application and after standing at 65 ° C. for 25 hours.

Creep The test piece and the stainless steel plate were bonded with the hot melt adhesive composition of each Example and Comparative Example in a range of 25 mm x 25 mm, and a static load of 1 kg was applied, and the mixture was left at 40 ° C for 3 hours. Then, the deviation width between them was measured.

Test results The results of each of the above tests are shown in the table.

Effects of the Invention According to the present invention, as is clear from the test results,
It can be understood that the pressure-sensitive adhesive is superior in adhesive strength to the conventional ones. In particular, the adhesive strength to polyethylene is greatly improved.

Moreover, the one using purified rosin as the raw material rosin is
Adhesion to polyethylene is further improved over that using unpurified gum rosin. Especially, it is particularly remarkable in the case where pentaerythritol is used as the polyhydric alcohol.

Further, those without addition of acrylic acid, although excellent in tack, as shown in Comparative Examples 3 and 4,
Poor adhesion, weak creep, and easy slippage of adhesion. It is also inferior in color tone.

In addition, for those that do not have asymmetric rosin,
As shown in Comparative Example 5, it can be seen that the adhesiveness immediately after the adhesion is good, but the adhesive strength is lowered after being left in a heated state, and the thermal stability is inferior.

Therefore, in the present invention, it can be understood that three requirements of addition of acrylic acid, asymmetry and esterification with polyhydric alcohol are indispensable to rosin.

Claims (8)

(57) [Claims] 1. A polyhydric alcohol ester of an asymmetric asymmetric rosin partially added with acrylic acid. 2. The addition rate of acrylic acid to the raw material rosin is
The rosin derivative according to claim 1, which is 2.3 to 45 mol%. 3. An addition reaction of acrylic acid to rosin, then a polyhydric alcohol is added to the acrylic acid addition product of the rosin, and an esterification reaction is performed while dehydrating,
A method for producing a rosin derivative, which comprises performing an asymmetric reaction of rosin at any stage of these reactions. 4. A pressure-sensitive hot-melt adhesive composition containing a block rubber, a tackifying resin and a plasticizer as main components, wherein the tackifying resin is a polyvalent polyvalent disproportionated rosin partially added with acrylic acid. Hot melt adhesive composition characterized by being an alcohol ester 5. The hot melt adhesive composition according to claim 4, wherein the block rubber is a polystyrene-polyisoprene-polystyrene block copolymer or a polystyrene-polybutadiene-polystyrene block copolymer. 6. The hot melt adhesive composition according to claim 4, wherein the rosin, which is a raw material of the tackifying resin, is purified. 7. The hot melt adhesive composition according to claim 4, wherein the addition ratio of acrylic acid to the raw material rosin in the tackifying resin is 2.3 to 45 mol% and the softening point of the tackifying resin is 100 to 100%. Hot melt adhesive composition characterized by having a temperature of 140 ° C. 8. A rosin is subjected to an addition reaction of acrylic acid, and then a polyhydric alcohol is added to the acrylic acid addition product of the rosin to carry out an esterification reaction while dehydrating,
A method for producing a hot melt adhesive composition, which comprises performing an asymmetric reaction of rosin at any stage of these reactions and mixing the obtained rosin derivative with a block rubber and a plasticizer.