JP2008045089A - Gel composition containing hydrogenated styrene block copolymer and tackifying resin - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a styrene gel having high adhesiveness, softness and strength, high vibration suppressing, vibration absorbing, cushioning and shock absorbing performance, low repulsion, and fall prevention, quake absorbing and seismic isolation performance, etc. <P>SOLUTION: The composition contains a hydrogenated styrene block copolymer and a tackifying resin. The hydrogenated styrene block copolymer is a polymer selected from styrene-ethylene-butylene-styrene block copolymer, styrene-ethylene-propylene-styrene block copolymer and styrene-ethylene-ethylene-propylene-styrene block copolymer or a mixture of two or more kinds of the above copolymers. The amount of the hydrogenated styrene block copolymer is 12-35 wt.% based on the total weight of the composition, the amount of the tackifying resin is 150-450 pts.wt. based on 100 pts.wt. of the hydrogenated styrene block copolymer and the composition has an Asker C hardness of 1-30 and tanδ of >1. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a thermoplastic gel composition having low hardness and excellent adhesiveness, and its use.

Conventionally, impact buffer materials using low-hardness vulcanized rubber, silicone gel, urethane gel, and impact buffer materials using metal springs have been used. However, it is difficult to reduce the hardness of impact buffer materials such as low-hardness vulcanized rubber, silicone-based gel, and urethane-based gel while maintaining various physical properties. There is also a problem of poor recyclability. In addition, the shock absorbing material using a metal spring has a problem that the shock energy is not attenuated indefinitely.
Recently, various techniques for reducing the hardness of styrene gel have been proposed (Patent Documents 1 to 6).
JP-A-2-300218 Japanese Patent Laid-Open No. 6-2933853 JP-A-8-41363 JP-A-9-263702 JP 2001-19861 A JP 2006-111758 A

However, the styrene gel disclosed in Patent Documents 1 and 2 has a high tan δ of around 1, and can be used for vibration damping materials, vibration damping materials, shock absorbing materials, shock absorbing materials, seismic isolation materials, and vibration proof materials. However, on the other hand, there is a problem that it is difficult to obtain sufficient mechanical properties when a softening agent or the like is included to reduce the hardness. Although the styrene gel disclosed in Patent Documents 3 and 4 has a low Asker C hardness of 25 to 75, tan δ is not sufficiently high as 0.05 to 1. The styrene gel disclosed in Patent Document 5 has low hardness and excellent impact buffering performance, but has low adhesiveness. The styrene gel disclosed in Patent Document 6 is used in a viscous gas get having both rigidity and flexibility, but the content of the tackifying resin is based on 100 parts by weight of the styrene block copolymer of the base resin. There is a problem that it is difficult to obtain a sufficient strength because the amount is as large as 500 parts by weight or more and the amount of the base resin is small.
Thus, conventionally, there is no styrene gel with high adhesiveness and high tan δ while maintaining both flexibility and strength, and vibration-proof materials, vibration-damping materials, shock-absorbing materials, shock-absorbing materials, low-rebound materials, and tipping prevention None of the materials, seismic isolation materials, and anti-seismic materials could be used.

  Therefore, the present invention is highly adhesive and has a high tan δ while achieving both flexibility and strength, and can be used as a vibration isolator, vibration damper, shock absorber, shock absorber, seismic isolator, seismic isolator, etc. The object is to provide high performance materials.

That is, the present invention is a composition containing a hydrogenated styrene block copolymer and a tackifying resin,
The hydrogenated styrene block copolymer is one or more selected from the group consisting of a styrene ethylene butylene styrene block copolymer, a styrene ethylene propylene styrene block copolymer, and a styrene ethylene ethylene propylene styrene block copolymer A mixture of
Containing 12 to 35% by weight of a hydrogenated styrene block copolymer, based on the total weight of the composition;
The tackifying resin is contained in an amount of 120 to 450 parts by weight based on 100 parts by weight of the hydrogenated styrene block copolymer.
Asker C hardness is 1-30,
It relates to a composition characterized in that tan δ> 1.

  According to the present invention, it is possible to obtain a thermoplastic gel composition having high adhesiveness and high tan δ while maintaining both flexibility and strength. This composition can be used as a well-balanced, high-performance material with strong adhesive strength, flexibility, high strength, and high vibration control, vibration isolation, shock absorption, shock absorption, low repulsion, seismic isolation, earthquake resistance, etc. .

  The hydrogenated styrene block copolymer in the present invention is a styrene ethylene butylene styrene block copolymer (SEBS), a styrene ethylene propylene styrene block copolymer (SEPS), or a styrene ethylene ethylene propylene styrene block copolymer (SEEPS). One or a mixture of two or more selected from the group consisting of

Prior to hydrogenation, styrene butadiene styrene copolymer (SBS) and styrene isoprene styrene copolymer (SIS) are problematic in that they are low in durability. In the hydrogenated block copolymer disclosed in Patent Documents 1 and 2 obtained by hydrogenating the isoprene portion of SIS having less than 70% of 1, 4 bonds, sufficient mechanical strength is obtained when the hardness is low. There is a problem that cannot be obtained.
However, since the hydrogenated styrene block copolymer is used in the present invention, a composition having sufficient mechanical strength can be obtained even with low hardness.

  The SEPS is usually obtained by reacting 90% or more of isoprene with 1, 4 bonds. Such SEPS is a block copolymer obtained by reacting 30% or more of 1,2 bonds and 3,4 bonds of isoprene disclosed in Patent Document 1 or 2 (that is, isoprene having 1,4 bonds). Block copolymers obtained by reacting less than 70%) and hydrogenated products thereof.

  The content of the hydrogenated styrene block copolymer in the composition of the present invention is such that a composition having sufficient mechanical strength can be obtained, or the ASCII C hardness of the resulting composition can be easily adjusted to 1 or more. In the total weight of the composition, it is 12% by weight or more, preferably 16% by weight or more, and the ASCII C hardness of the resulting composition can be easily adjusted to 30 or less, or it can be sufficiently gelled with a twin screw extruder. Or less, preferably 30% by weight or less, based on the total weight of the composition.

  The number average molecular weight of the hydrogenated styrene block copolymer is not particularly limited, but is preferably 100,000 or more from the viewpoint of increasing the mechanical strength of the resulting composition. Although about 400,000 can be used, the upper limit is not limited.

As tackifying resin in this invention, it is preferable to use 1 or more types chosen from the group which consists of rosin resin, terpene resin, petroleum resin, coal resin, phenol resin, xylene resin etc., for example.
Examples of the rosin resin include gum rosin, tall oil rosin, wood rosin, hydrogenated rosin, disproportionated rosin, polymerized rosin, and modified rosin.
Examples of the terpene resin include α-pinene terpene resins, β-pinene terpene resins, dipentene terpene resins, aromatic modified terpene resins, terpene phenol resins, and hydrogenated terpene resins.
Examples of the petroleum resin include aliphatic (C5) petroleum resin, aromatic (C9) petroleum resin, copolymer (C5 / C9) petroleum resin, alicyclic (hydrogenated, dicyclopentadiene ( DCPD) type petroleum resin, styrene type (styrene type, substituted styrene type) petroleum resin, and the like.
Examples of the coal resin include coumarone / indene resin.
Among these, in addition to obtaining excellent heat resistance and compatibility, a terpene resin is preferable for achieving tan δ> 1, and a hydrogenated terpene resin is most preferable from the viewpoint of weather resistance.

  The content of the tackifying resin in the composition of the present invention is 120 parts by weight or more, preferably 100 parts by weight of the hydrogenated styrene block copolymer, from the viewpoint that the tan δ and tackiness of the resulting composition are increased. It is 150 parts by weight or more, and the ASCII C hardness of the resulting composition can be easily adjusted to 30 or less, whereby it can be matched with the adhesive surface, and the substantial tackiness of the composition is increased. To 450 parts by weight or less, preferably 400 parts by weight or less.

The ASCII C hardness of the composition of the present invention is 1 or more, preferably 5 or more in order to obtain a high mechanical strength, and is 30 or less because it can be easily aligned with the adhesive surface and the substantial adhesiveness is increased. , Preferably 25 or less.
The ASCII C hardness can be adjusted depending on the type, molecular weight, content, and the like of the styrene block copolymer or tackifier.

The composition of the present invention exhibits tan δ> 1. This tan δ is a peak value at a frequency of 1 Hz. In the viscoelasticity test, tan δ is called G ″ / G ′, which is the ratio of storage shear modulus (G ′) to loss shear modulus (G ″), loss tangent (loss factor). It shows how much energy the material absorbs (changes to heat). Therefore, the higher this tan δ, the higher the performance of vibration control, vibration isolation, shock absorption, shock absorption, seismic isolation, vibration isolation, and the like. These performances can be exhibited even when tan δ is 1 or less, but tan δ exceeds 1, preferably 2 from the viewpoint of thinning the composition and reducing the cost.
Since tan δ is temperature dependent, the above effect can be more effectively exhibited when the peak temperature is close to the actual use temperature of the composition. Therefore, the peak temperature may be appropriately selected according to the actual application, but is preferably 0 to 40 ° C. from the viewpoint of practicality. The peak temperature and the tan δ value can be adjusted depending on the type, molecular weight, content, etc. of the styrene block copolymer or tackifier.

The composition of the present invention may contain a softening agent from the viewpoint of increasing the adhesiveness, and for example, may be contained in an amount of 0 to 200 parts by weight with respect to 100 parts by weight of the hydrogenated styrene block copolymer.
The softener can be appropriately selected from the group consisting of, for example, various rubbers such as mineral oils, vegetable oils, and synthetics, and resin softeners. Examples of mineral oils include naphthenic, paraffinic and aromatic process oils, and vegetable oils include castor oil, cottonseed oil, linseed oil, rapeseed oil, soybean oil, palm oil, coconut oil, peanut Examples include oil, wax, pine oil and olive oil. Among these, from the viewpoint of purity, heat stability, etc., one or more selected from non-aromatic oils, particularly mineral oil-based paraffinic oils, naphthenic oils or synthetic polyisobutylene-based oils are preferred. .
The number average molecular weight of the softening agent is preferably 300 or more, particularly 350 or more from the viewpoint of suppressing bleeding out, and preferably 1000 or less, particularly 800 or less from the viewpoint of suppressing stickiness.

  In addition to hydrogenated styrene block copolymers, tackifying resins, and softeners, the composition of the present invention includes resins, plasticizers, lubricants, flame retardants, inorganics, as long as they do not impair flexibility and mechanical strength. Additives, plasticizers, lubricants, flame retardants, stabilizers, anti-cracking agents, antioxidants, UV absorbers, anti-aging agents, antiozonants, antifungal agents, antifungal agents, dispersants, coloring pigments, electrification One or more suppressors can be contained.

There is no restriction | limiting in particular in the manufacturing method of the composition of this invention, A well-known method is applicable. For example, the above-mentioned materials and desired additive components are melted using a heat kneader, such as a single screw extruder, twin screw extruder, roll, Banbury mixer, Brabender, kneader, high shear mixer, etc. Kneading and then adding a crosslinking agent such as an organic peroxide, a crosslinking aid, etc., if necessary, or mixing these necessary components simultaneously or after a while, by heating and melting and kneading, It can be manufactured easily.
Furthermore, after press molding, extrusion into a sheet, etc., it can be cut into a predetermined size, or molded into a predetermined shape by injection molding or the like. It is also possible to use a metal plate such as a resin film, aluminum, or stainless steel on one side.

EXAMPLES Hereinafter, although an Example demonstrates this invention further in detail, this invention is not limited by this. The evaluation method is as follows.
The number average molecular weight was measured by gel permeation chromatography [GPC; Tosoh GMH-XL (two in series)] and converted into polystyrene using monodisperse polystyrene as a standard using the differential refractive index (RI).
The measurement of tan δ was performed at a frequency of 1 Hz using a viscoelasticity measuring device (manufactured by Rheometrics).
The Asker C hardness was set to a value after 5 seconds using a 5 mm thick sample using an Asker C hardness meter.
The tensile fracture strength was measured according to JIS K 6251.
The adhesive strength was defined as the maximum value of strength when a 30 mm × 30 mm × 1 mm sample was sandwiched between stainless steel plates and pulled vertically at 300 mm / min.

(Example 1)
According to the composition ratio shown in Table 1, a lab kneading machine “Plastomil” was prepared by using a styrene ratio of 33%, SEPS having a number average molecular weight of about 200,000, hydrogenated terpene resin (softening point 105 ° C. product), and paraffin oil having a number average molecular weight of 400. Toyo Seiki Co., Ltd.) was mixed at 180 ° C. and 50 rpm for 30 minutes, and then pressed to prepare sheets of various thicknesses.
The evaluation results of the sheet are shown in Table 1. The tan δ is 3.1 at a peak temperature of 4 ° C., the Asker C hardness is 20, the tensile breaking strength is 3.0 MPa, the adhesive strength is 19.5 N / cm ^2, and tan δ, flexibility, strength, and adhesiveness are good. Indicated.

(Examples 2 to 5)
Example 2 is a hydrogenated terpene having a softening point of 125 ° C., and the composition is the same as that of Example 1 except that paraffin oil having a number average molecular weight of 520 is used. Examples 3 and 4 are hydrogenated terpenes having a softening point of 150 ° C. The composition is the same as that of Example 2 except that the styrene ratio of the styrene block copolymer is 29% and the number average molecular weight is 140,000. The sheets were prepared in accordance with the composition ratios in Table 1 with various compositions.
Table 1 shows the evaluation results of the sheet. All showed good tanδ, flexibility, strength, and tackiness.

(Comparative Example 1)
A sheet was prepared according to the composition ratio shown in Table 1 with the same composition as in Example 5 except that paraffin oil having a number average molecular weight of 750 was used. Since the amount of terpene is large, the tensile strength at break is low. Moreover, although Asker C hardness was 12, the touch feeling was hard, and it had the characteristic that it was too low repulsion that 35 initially became 12 after 5 seconds, and there was a problem with bad handling (Table 1).
(Comparative Example 2)
A sheet was prepared according to the composition ratio shown in Table 1 with the same composition as in Examples 3 and 4 except that paraffin oil having a number average molecular weight of 360 was used. Since the amount of terpene was small, tan δ and adhesive strength were extremely low (Table 1).
(Comparative Example 3)
The composition and its ratio were the same as in Example 5 except that the styrene ratio was 20% and the hydrogenated SIS had 1,2 bonds and 3,4 bonds of 80%. A sheet was produced. Compared to Example 5, the tensile strength at break was low and fragile.

The composition of the present invention can be used in various industrial fields such as a fixing member, a supporting member, a vibration damping material, a vibration damping material, a shock absorbing material, a shock absorbing material, a low repulsion material, a fall prevention material, a seismic isolation material, and a vibration damping material. , Household appliances, sports equipment, industrial equipment, acoustic equipment, information / precision equipment, transportation equipment, game equipment, architecture, civil engineering, medical care, leisure, etc., especially coolers, washing machines, refrigerators, electric fans, It is suitably used for devices that generate vibration / sound such as vacuum cleaners, dryers, printers, blowers, etc., or household electrical appliances, vehicle seat materials, seismic isolation rubbers, anti-vibration rubbers, and racing tires.
Specifically, as a fixing member, sealing materials, packing, gaskets, grommets, etc., as a supporting member, mounts, holders, insulators, etc., as shock absorbers, stoppers, cushions, bumpers, etc., as vibration proof materials, printer print heads Used for parts. Furthermore, it is also used for OA equipment as ultra-low hardness rubber. Preferably, as a fall prevention material, furniture such as chests, lockers, bookshelves, flat panel displays (FPDs) such as flat-screen TVs, liquid crystal displays, household appliances such as refrigerators, office equipment such as printers and personal computers, etc. Can be used for prevention equipment.

Claims (10)

A composition containing a hydrogenated styrene block copolymer and a tackifying resin,
The hydrogenated styrene block copolymer is one or more selected from the group consisting of a styrene ethylene butylene styrene block copolymer, a styrene ethylene propylene styrene block copolymer, and a styrene ethylene ethylene propylene styrene block copolymer A mixture;
Containing 12 to 35% by weight of a hydrogenated styrene block copolymer, based on the total weight of the composition;
The tackifying resin contains 120 to 450 parts by weight with respect to 100 parts by weight of the hydrogenated styrene block copolymer;
Asker C hardness is 1-30;
tan δ> 1
The composition characterized by the above-mentioned.   The composition according to claim 1, wherein the hydrogenated styrene block copolymer is contained in an amount of 16 to 30% by weight based on the total weight of the composition.   The composition according to claim 1 or 2, wherein the number average molecular weight of the hydrogenated styrene block copolymer is 100,000 or more.   The composition according to any one of claims 1 to 3, wherein the tackifying resin is a terpene resin.   The composition according to claim 1, wherein the Asker C hardness is 5 to 25.   The composition according to claim 1, wherein tan δ> 2.   The composition according to any one of claims 1 to 6, comprising 0 to 200 parts by weight of a softening agent with respect to 100 parts by weight of the hydrogenated styrene block copolymer.   The composition according to claim 7, wherein the number average molecular weight of the softening agent is 300 to 1,000.   The composition according to claim 7 or 8, wherein the softening agent is one or a mixture of two or more selected from the group consisting of naphthenic oil, paraffin oil, and aromatic oil.   A vibration-proof material, a vibration-damping material, a shock-absorbing material, a shock-absorbing material, a low-resilience material, a fall-preventing material, a seismic-isolating material, or a vibration-proof material, comprising the composition according to claim 1.