JPS6253386A - Hot-melt adhesive composition - Google Patents

Abstract

PURPOSE:A hot-melt adhesive composition having improved bonding performance to polyolefin base materials having difficulty in bonding, improved workability, heat stability, etc., containing specific two styrenic copolymers, a pressure- sensitive adhesive, wax, etc. CONSTITUTION:The aimed adhesive composition containing (A) a styrene- isoprene-styrene block copolymer, (B) a copolymer obtained by hydrogenating the styrene-isoprene-styrene block copolymer or a styrene-butadiene-styrene block copolymer, (C) an adherent resin and (D) wax or hydrocarbon synthetic rubber having >=300 number-average molecular weight and <=120 deg.C pout point. EFFECT:Causing neither change in performance resulting from vapor distillation during heating nor staining of materials to be bonded.

Description

Detailed Description of the Invention (a) Purpose of the Invention [Field of Industrial Application] The present invention is widely used in various industrial fields. This hot melt adhesive has excellent adhesion to plastics and excellent thermal stability when melted by heating, and can be used in a wide variety of industrial fields.

[Conventional technology]

Conventionally, polyolefin plastics such as polypropylene and polyethylene have been known as difficult-to-adhere materials due to the non-polar surface and crystallinity of their surfaces, and various methods of bonding these materials have been studied.

These methods include (1) a method of thermally adhering the same materials to each other by heat sealing, ultrasonic bonding, etc.; (2)
Methods of increasing adhesive strength by treating the surface of the material.For example, oxidizing the surface with acid solution treatment, electric discharge, ultraviolet irradiation, or radiation irradiation to introduce polar groups, or short-term immersion in chlorine-based solvents. There are methods such as roughening the surface to increase the flow of adhesive, or coating the surface with a brimer coat with chlorinated polypropylene, silane cutting agents, etc., but method (1) is only suitable for bonding similar materials. Not only that, but it also has the disadvantage of damaging the material itself due to thermal deformation.
In method (2), the number of adhesion steps increases, and no method has been found that has satisfactory adhesion performance itself.

Furthermore, a method of bonding such difficult-to-bond materials using pressure-sensitive adhesives, that is, tackiness, is being considered, but when using pressure-sensitive adhesive sheets, the number of steps in the bonding process increases, and it is not suitable for bonding molded objects. Another problem is the processing cost of the adhesive sheet.

In addition to these, a pressure-sensitive adhesive using a styrene-isoprene-styrene block copolymer was published in 1973.
037. Special Publication No. 47-21720 Special Publication No. 48-9932
et al., it has been proposed that a specific adhesive resin be added to a styrene-butadiene-styrene block copolymer or a styrene-isoprene-styrene block copolymer, or that a process oil called a paraffin-type Pressure-sensitive adhesives containing high-boiling petroleum fractions such as hydrocarbons, naphthenic hydrocarbons, and aromatic hydrocarbons, liquid rosin, and liquid terpene have been proposed, but these have poor adhesion to difficult-to-adhere materials. Even if adhesion is obtained, when melt coating is used as a hot melt adhesive, there may be a decrease in melt viscosity in the heated melting tank that may be caused by the block copolymer or before weight increase. There is a problem with the resulting decrease in adhesive strength and volatilized vapor during melting, which is thought to be due to the increase in adhesive strength, that is, there is a problem with thermal stability during heating and melting.

[Problem that the invention seeks to solve]

The present invention has excellent adhesion performance to the above-mentioned polyolefin base material, which is said to be extremely difficult to adhere to, and when used as a hot melt adhesive, it improves workability in melt application equipment and The aim is to provide a hot-melt adhesive composition that has excellent heating stability and is free from performance changes due to vapor volatilization during heating and from contamination of adhesive materials. The aim is to provide a composition that can be applied up to drugs.

(B) Structure of the Invention [Means for Solving the Problems] The present inventors have continued to conduct intensive studies on compositions that provide excellent hot melt adhesives that do not have the above-mentioned problems, and have developed compositions containing four specific components. The present invention was completed based on the discovery that the above requirements were satisfied.

That is, the present invention relates to a hot melt adhesive composition characterized by containing the following four components.

(5) Styrene-isoprene-styrene block copolymer (B) A copolymer obtained by hydrogenating a styrene-isoprene-styrene block copolymer or a styrene-butadiene-styrene block copolymer (q adhesive resin p ) Wax or number average molecular weight of 600 or more and pour point of 1
A hot melt adhesive obtained from a hydrocarbon synthetic rubber composition having a temperature of 20° C. or lower has excellent adhesion to polyolefin plastics and excellent thermal stability during heating and melting.

o(AI) Styrene-isoprene-styrene block copolymer The styrene-isoprene-styrene block copolymer as a four-component used in the present invention is commonly known as a SIS-based thermoplastic di-stomer, for example. , "Califlex TR-11" manufactured by Shell Chemical Co., Ltd. is a commercially available product.
07""Cariflex TR-1111JrCariflex TR-1112JrCariflex TR-1117
"and so on.

0(B) Styrene-isoprene-styrene or styrene-butadiene-styrene block copolymer obtained by hydrogenating a styrene-inprene-styrene block copolymer or a styrene-butadiene-styrene block copolymer as the same component. Since it is a copolymer obtained by hydrogenating a polymer, for example, as a commercially available product manufactured by Shell Chemical Co., Ltd. [Krayton G-1650jr Kraton G
-1,551J "There are Clayton G-1652Jr, Clayton G-1657J, etc.

In the present invention, a copolymer containing 65% by weight or less of styrene units in the copolymer of component (5) and component (B) is desirable.

The proportion of the four-component styrene-isoprene-styrene block copolymer and the copolymer obtained by hydrogenating component (B) used in the present invention is such that, in terms of weight ratio, the above-mentioned copolymer is 90% by weight of the total amount of both. % or less is preferably 60% by weight or more, and if it is used in an amount exceeding 90%, the thermal stability of the composition during heating and melting will decrease.

If it is less than 60 inches, the adhesive strength to polyolefin materials, especially polypropylene materials, will decrease.

More preferably, the weight ratio of each is 80:20 to 50:
50 range.

0 (C) Adhesive resin As the adhesive resin, natural rosin as a rosin type,
Examples of polymerized rosins and their derivatives include C, pentaerythrite ester rosin, chrycerin ester rosin, and hydrogenated resins thereof.Specifically, commercially available products include GUMLO, gin, wood rosin, ester gum A, and ester gum. Examples include Bencel A, Bencel C (Arayo Kagaku Kogyo ■), Pentaline A, 7 Oral AX, 7 Oral 85, Foral 105, and Pentaline C (Rika Vercules ■). In addition, terpene-based resins include polyterpene resins, terpene phenol resins, and hydrogenated resins thereof. Specifically, commercially available products include Picolite 81 Picolite A (Pico Co., Ltd.), YS Resin (cheap crude oil), and YS Polyster T (Yasuhara). oils and fats), and Clearon (cheap crude oil). Furthermore, petroleum resins include aliphatic petroleum resins, aromatic petroleum resins, copolymer petroleum resins, and hydrogenated petroleum resins.Specifically, commercially available products include Escorets (Toho Oil Resin■) , Hilets (Mitsui Petrochemical ■), Finton (Nippon Zeon ■), Wingtac (Gutdeyer ■), Statac (Reichhold ■), Toho Betrozin (Toho Oil Resin ■), 8 Stone Neopolymer (Japan Petrochemical ■) , Vetrozin (Mitsui Petrochemical ■), Tac Ace (Mitsui Petrochemical ■), Escorez (Esso Chemical ■), Toho Hi Resin (Toho Oil Resin ■), Super Star Tatsuku (Reichhold ■)
), Alcon P and M (Arayo Kagaku Kogyo ■), and Picovert (Pico Inc. ■). In the present invention, these adhesive resins can be used depending on the purpose, but hydrogenated resins are preferred for the present invention.

These adhesive resins are used to increase the adhesive properties to the adherend material, and the blending amount is 60 parts by weight or more and 300 parts by weight per 100 parts by weight of the copolymer of components (5) and (B). It is preferably less than 50 parts, more preferably 50 parts or less.
If the blending amount is less than 60 parts, it will be difficult to obtain sufficient adhesion to polyolefin materials, which is a feature of the adhesive according to the present invention; If it exceeds this, the cohesive force of the adhesive will decrease, and the adhesive force will decrease. Also, adhesive resins whose softening points are 60° C. or higher and 150° C. or lower are preferred for the present invention.

0(D) Wax or hydrocarbon synthetic rubber having a number average molecular weight of 300 or less and a pour point of 120°C or less The wax used in the present invention includes paraffin wax, microwax, low molecular weight polyethylene, low molecular weight polypropylene, etc. This is used to increase the fluidity and non-stick properties of the adhesive composition when it is melted. Paraffin wax is generally a solid hydrocarbon separated from the high-boiling fraction of crude oil and is commercially available from, for example, Nippon Oil Co., Ltd. and Nippon Seiro Co., Ltd. Microwax is generally a high-melting wax purified from a high-boiling fraction of crude oil, and commercially available products include 8-stone microwax (Nippon Oil ■) and Hymic (Nihon Sekisen ■). Low molecular weight polyethylene is generally obtained by polymerizing ethylene alone or by copolymerizing other α-olefins, and usually has a softening point of 80°C or higher and 140°C.
Waxes below ℃ such as AC polyethylene (Allied Chemical ■), Hoechst wax PE (Hoechst ■)
, Mitsui Hiwax (Mitsui Petrochemical ■), Neowax (cheap crude oil ■), and Sunwax (Sanyo Chemical Industries ■). Low molecular weight polypropylene is generally obtained from a low polymerization degree of propylene or by oxidative decomposition of polypropylene. ■) etc.

The hydrocarbon synthetic rubbers used in the present invention having a number average molecular weight of 300 or more and a pour point of 120°C or less include polybutene, polyisobutylene, polyimprene, polybutadiene, and hydrogenated products thereof. It is preferable to have no functional groups other than unsaturated groups in the molecule.
Furthermore, polybutene, which has no unsaturated bonds in the side chain, 1
, 4-polyisoprene, polyisobutylene, and 1,4-polybutadiene are preferred, and polybutene, polyisobutylene, and hydrogenated synthetic rubber having no unsaturated groups other than at least the terminals are more preferred. Specifically, examples include Kuraprene LIR1 hydrogenated LIR (Clare Isoprene Chemical), Idemitsu polybutene (Idemitsu Petrochemical), 8-stone polybutene (Nippon Petrochemical), and Tetranx (Nippon Petrochemical). Such synthetic rubber not only significantly improves adhesion and cold resistance to polyolefin materials, but also provides a composition with excellent fluidity when melted. However, if the number average molecular weight of the synthetic rubber is less than 600, volatilized vapor during heating and melting may be obtained. If the pour point exceeds 120° C., not only the compatibility of the adhesive composition will be insufficient, but also the cold resistance of the adhesive will be significantly impaired. The blending ratio of wax and synthetic rubber can be freely selected depending on the application without sacrificing the characteristics of the present invention, such as adhesion to polyolefin materials and thermal stability during heating and melting. The non-adhesiveness of
It improves heat resistance, especially creep strength, and conversely, increasing the amount of synthetic rubber improves the cold resistance of the adhesive and increases tackiness, making it possible to use it as a heat-sensitive and pressure-sensitive adhesive. is preferably 10 parts by weight or more and 300 parts by weight or less based on 100 parts by weight of the copolymer, and 10 parts by weight or less.
If it is less than 1 part by weight, the fluidity during melting will be insufficient,
Adhesive coating properties may be impaired. On the other hand, if it exceeds 300 parts by weight, the adhesion to the polyolefin material itself will be impaired. As mentioned above, for the present invention,
For the purpose of imparting tackiness to the A-B-A type block copolymer used in the present invention, bulking oil or process oil is a petroleum-based high boiling distillate of sulparaffinic, naphthenic, or aromatic hydrocarbon type. Compositions containing liquid rosin, liquid terpene, etc. have already been reported, but these bulking oils reduce the cohesive force of the composition and significantly impair the adhesive heat resistance, especially the creep resistance. However, it is not suitable for achieving the object of the present invention because it impairs the heating stability during melting, which is a feature of the product, and furthermore, there is a problem of contamination of the adhesive material by volatilized vapor during melting. EVA%E used in the present invention within a range that does not impair
EA, saponified BVA, ethylene-propylene copolymer, etc. As aggregates, for example, talc, silica, calcium carbonate,
It is also possible to add zinc white or the like within a range that does not impair the characteristics of the present invention.

Furthermore, an antioxidant may be added to the composition of the present invention, preferably within a range of 6% based on the total composition.

In such a composition, the hot melt adhesive composition of the present invention can be obtained, but in consideration of the coatability when melted, it is preferable that the melt viscosity of the composition of the present invention does not exceed 100,000 CpS/200°C. The softening point is preferably 60°C or more and 150°C or less.

0 Manufacturing method of adhesive The adhesive made from the composition of the present invention can be produced by a method in which each component is melted at 1 nj or sequentially by rotating a heating type melting stirring blade, or by a method in which the components are melted at 1 nj or in sequence using a fork-shaped rotary blade called a ni-goo under heating. It can be produced by any method commonly used in the production of hot melt adhesives, such as a mixing method or a method of melt-mixing under heating using an extruder, that is, a single or twin screw screen.

[For production]

The hot melt adhesive composition containing four components of the present invention has the effect of providing an adhesive with excellent adhesion performance to polyolefin II resins, which are difficult to adhere to, due to the coexistence of the four components. Moreover, the adhesive has excellent workability in melt coating equipment, excellent heating stability during melting, no performance change due to vapor volatilization during heating, and no contamination of the adhesive material. Excellent effects were achieved only by using the four components in combination.

[Examples and comparative examples]

O Evaluation Method R&B Softening Point: Measured according to JIS-2207.

Melt viscosity: 19 according to JAI-7-1980
The mixture was heated to 0°C and measured using a B-type rotational viscometer.

Melt stability...Hoctomelt aggregator Nordson X [W (Nordson ■)! After bath dissolution at @190°C for 10 hours, the viscosity of the adhesive discharged from the gun was measured by the method described above to examine the decrease in viscosity.

Vapor volatilization: Fuming from the resin discharged in the above method was visually observed.

Adhesive strength: After 2 hours have elapsed after the adhesive bath-melted in the above method is put into a hot melt applicator, a polypropylene film of 10crIL square (ROOOt
t) at a coating weight of 5'g/m in the form of a string, and after 10 seconds, 51 sheets of polypropylene film (600μ) were adhered with a manual pressure lid.

The adhesive piece was cut to a width of 25% and the T-peel strength was measured.

The measurement temperatures were room temperature (below 25°C), 0°C, and 50°C.

The tensile speed was measured at 200%/-". Similarly, 1o
Adhesion performance after hours was also measured.

Examples 1-8. Comparative Examples 1 to 3 Microwax +155 (softening point 155°F: Nippon Petrochemical (Silent) 1ky, I rganox-1010 as an antioxidant was placed in a 10A' melting stirring tank heated to 200°C.
(Polymer hindered polyhydric phenol: Teva-Geigy sphere)
Melt and stir the 30&, add the molten layer, and add the tackifier Alcon P.
-115 (Hydrogenated petroleum resin: Softening point 115℃: Arayo Chemical)
1, gradually add y, and after raising the liquid temperature to 200℃, the force of the copolymer')7V7xTk-110'7 900#,
After adding L/ite 7G-1657ioo and li', the mixture was stirred for 2 hours, and after confirming dissolution, it was extracted from the tank to obtain an adhesive.

The results of evaluation using the above evaluation method are shown in the table as Example 1. In the same manner, the base resin of Example 10 was changed to TR-1107 to G-1657 in a weight ratio of 70 parts, 750 parts, and 50 parts, 15 parts.
Examples 2 to 4 were 0 part, 30 parts, and 770 parts.

In addition, compared with the same TR-1107 and G-1657 as in Example 3 with a heavy debt ratio of 50 parts and 150 parts, the adhesiveness (hydrogenated rosin glycerin ester softening point 75 ° C.) was higher than that of ys polyster T-115 (Teru Polybutene 2 [100H (pour point 20°C:
Molecule 12400: Hydrogenated polybutene system: Example 8 uses Idemitsu Petrochemical.

As a comparative example, TR-1107 and G-1 were used as copolymers.
Comparative Examples 1 and 2 are those in which 657 was used alone, and Comparative Example 6 is one in which Shell Flex 371 J (JLI naphthene oil: Shell Chemical) was used as an extender oil instead of wax and liquid synthetic rubber. Shown below.

The manufacturing method was the same as [Example 1].The adhesives obtained in Examples 1 to 7 and Comparative Examples 1 to 2 belong to true melt adhesives that are not sticky at room temperature. The adhesives obtained in Example 8 and Comparative Example 3 belonged to pressure-sensitive hot melt adhesives.

(c) Effects of the Invention The adhesive composition of the present invention has excellent adhesion to olefin plastic materials, which was difficult to achieve with conventional hot melt adhesives, and also has excellent adhesion by melt application using a hot melt applicator called a product assembly. It is possible to provide a hot melt adhesive having high heating and melting stability, and it has an excellent effect that it can be effectively used in various industrial fields including packaging and assembly.

Claims (1)

[Claims] 1. A hot melt adhesive composition characterized by containing the following four components. (A) Styrene-isoprene-styrene block copolymer (B) Copolymer obtained by hydrogenating styrene-isoprene-styrene block copolymer or styrene-butadiene-styrene block copolymer (C) Adhesive resin (D) Wax or hydrocarbon synthetic rubber having a number average molecular weight of 300 or more and a pour point of 120°C or less