JP2005105128A - Method for regulating adhesion of gel, gel having adhesion regulated by the method, and gel radiating little voc - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for regulating adhesion of a gel; to provide the gel having the adhesion suitable for an application and imparted by the method; and to provide the gel radiating little VOC. <P>SOLUTION: The method for regulating the adhesion of the gel containing a styrenic block copolymer and a softener, or reducing the radiation of a volatile organic compound (VOC) involves regulating a weight average molecular weight of the softener. The gel having the adhesion regulated by the method, and the gel radiating the little VOC are also provided. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a method for controlling the adhesiveness of a gel, a gel whose adhesiveness is controlled by this method, and a low VOC gel. The present invention also relates to a gel suitable for an article used in contact with the human body, an anti-slip material or a vehicle interior material.

  As a gel that has shock absorption properties and is used for vibration-proof materials, vibration-damping materials, shock-absorbing materials, dampers, etc., it combines thermosetting polyurethane and other resins such as vinyl chloride polymers and plasticizers. Mainly composed of styrene block copolymer mixed with softener, ethylene block copolymer mixed with softener, polydiorganosiloxane with low crosslink density, polydiorganosiloxane and polyisobutylene. A mixed system as a component has been proposed.

  As the thermosetting polyurethane, for example, as disclosed in Patent Document 1 and Patent Document 2, a high molecular weight polyol, a low molecular weight polyhydric alcohol and a monohydric alcohol are blended and reacted with a polyisocyanate. A low-hardness thermosetting polyurethane with improved mechanical properties is used. As the high molecular weight polyol, in Patent Document 1, a polyoxypropylene-based polyol having an average molecular weight of 1,000 to 6,000 is used, and in Patent Document 2, polybutadiene having a hydroxyl group at the terminal is used. As low molecular weight polyhydric alcohols, in addition to ordinary polyhydric alcohols such as 1,4-butanediol and glycerin, Patent Document 1 describes the use of polyether polyols having a weight average molecular weight of up to 700.

  In Patent Document 3, a vinyl chloride polymer impregnated with a plasticizer and then formed into a composite with polyurethane has a soft and non-sticky feel, excellent design, and various protective covers. Is disclosed.

In Patent Document 4, a styrene-butadiene-styrene block copolymer and / or a hydrogenated product thereof is mixed with a styrene-isoprene-styrene block copolymer and / or a hydrogenated product thereof, or a polyphenylene ether resin. In addition, a vibration damping material containing polypropylene or a softening agent is disclosed. In Patent Document 5 and Patent Document 6, a softening agent is blended into a system composed of the above triblock styrene elastomer rich in elasticity and a diblock styrene elastomer excellent in shock absorption and shock relaxation properties. Thus, a shock-absorbing gel composition is disclosed. Furthermore, Patent Document 7 describes a gel in which a softening agent is blended with a block copolymer composed of a polyethylene segment and an ethylene-styrene random copolymer segment.
JP-A-6-73150 Japanese Patent Publication No. 6-92478 JP 2000-141466 A Japanese Patent Laid-Open No. 11-12430 JP 2001-151979 A JP 2001-342283 A JP-A-5-239256

A mixed gel of a styrenic block copolymer having thermoplasticity and a softening agent is thermoplastic and therefore has poor heat resistance. In order to reduce the hardness of the gel, a large amount of a softening agent such as paraffinic process oil or vegetable oil is added to the polymer. Therefore, in such a gel, stickiness is increased and bleeding of the softening agent is likely to occur.
Therefore, such gels cannot be used in places where the temperature is high, and low hardness gels with reduced hardness are often sticky, so they are not easy to handle and feel poorly. Use was limited.
Furthermore, a gel containing such a large amount of softening agent tends to generate volatile organic compounds and may adversely affect human health and electronic equipment. Therefore, it is a building material used in a sealed space. , Use in interior materials such as vehicles, home appliances, etc. will be restricted.

  An object of the present invention is to provide a method for controlling the adhesiveness of a gel, a gel imparted with an adhesive suitable for use by the method, and a gel that generates little or no volatile organic compounds. is there.

  As a result of intensive studies, the present inventors have found that the above problem can be solved by adjusting the weight average molecular weight of the softener in a gel containing a styrenic block copolymer and a softener. Completed the invention.

  That is, the present invention relates to a method for controlling the tackiness of a gel containing a styrenic block copolymer and a softening agent, the method comprising adjusting the weight average molecular weight of the softening agent, and the sticking by this method. It relates to a gel with controlled properties and a gel imparted with low VOC properties. In the present invention, the low VOC property means a property that little or no volatile organic compound (VOC) is generated.

(1) According to the method of the present invention, the gel tackiness can be freely controlled from non-tackiness to high tackiness. Moreover, according to this invention, the gel which has the adhesiveness suitable for a use can be obtained. For example, it is possible to use a gel imparted with high tackiness by the method of the present invention for a portion that requires high tackiness. It becomes possible to use a gel imparted with low tackiness.
(2) In the present invention, by using a styrene block copolymer having a large weight average molecular weight, the heat resistance and mechanical properties of the gel containing the styrene block copolymer can be improved.
(3) In the present invention, a tackifier may be added to the gel in some cases. In this case, the heat resistance of the gel containing the tackifier is reduced by using a tackifier having a high softening point. In addition, the hardness of the gel can be lowered without increasing the amount of softening agent.
(4) In the method of the present invention, heat resistance is imparted to the gel, so that it is possible to obtain a gel that can be melted by applying heat with an iron or the like overlaid on the cloth.
(5) The gel of the present invention is excellent in shock absorption and vibration damping properties, and can be used for vibration damping materials, vibration damping materials, buffer materials, dampers, and the like.
(6) The gel of the present invention can suppress the volatility of the softener and reduce the generation amount of volatile organic compounds such as formalin by increasing the weight average molecular weight while containing a large amount of the softener. . Moreover, by using together with antioxidant, the quantity of the volatile organic compound which generate | occur | produces by oxidative decompositions, such as a softener and a styrene-type block copolymer, can also be reduced.
As described above, the gel of the present invention is highly safe for the human body because the amount of volatile organic compounds generated is suppressed.
Therefore, the gel of the present invention can be used in fields where conventional products could not be used due to generation of volatile organic compounds, such as building materials, vehicle interior materials or home appliances, and articles used in contact with the human body. Can be used.

In the present invention, by adjusting the weight average molecular weight of the softening agent, the tackiness of the gel containing the softening agent can be controlled, and the generation of volatile organic compounds can be reduced.
That is, increasing the weight average molecular weight of the softening agent increases the tackiness of the gel containing the softening agent, but decreasing the weight average molecular weight of the softening agent decreases the tackiness of the gel containing the softening agent. .
Moreover, if the weight average molecular weight of the softening agent mix | blended with a gel is enlarged, generation | occurrence | production of the volatile organic compound from a gel will reduce.
In the present invention, the weight average molecular weight of the softening agent is measured by a gas chromatography method.

The present invention relates to a gel comprising a styrenic block copolymer and a softening agent, wherein the softening agent has a weight average molecular weight of 250 or more. The present invention also relates to a gel having adhesiveness and / or low VOC properties according to the use, which is obtained by appropriately adjusting the weight average molecular weight of the gel softener.
For example, in order to obtain a non-adhesive or relatively low-viscosity gel by the method of the present invention, the smaller the weight average molecular weight of the softening agent blended in the gel, the better. . However, in order to impart good heat resistance to the gel, the weight average molecular weight of the softener blended in the gel is 250 or more, preferably 300 or more, more preferably 350 or more.
Moreover, in order to obtain a gel with relatively high tackiness by the method of the present invention, the larger the average molecular weight of the softener blended in the gel, the better, and it is usually preferably 400 or more.
Furthermore, in order to obtain a gel having relatively high adhesiveness and low VOC properties, it is preferable that the weight average molecular weight of the softener is 450 or more, particularly 500 or more, particularly 535 or more.
The weight average molecular weight of the softening agent is usually 700 or less, preferably 650 or less, and more preferably 600 or less in order to obtain good mixing properties, moldability, or suppress stickiness.

The styrenic block copolymer used in the present invention is a component that imparts softener retention and elasticity to the gel.
In the present invention, by using a styrene block copolymer having a large weight average molecular weight, the heat resistance and mechanical properties of the gel containing the styrene block copolymer can be improved.
In the present invention, in order to impart good heat resistance and mechanical properties to the gel, it is desirable that the weight average molecular weight of the styrenic block copolymer contained in the gel is as large as possible. For example, 250,000 or more is preferable. 300,000 or more is more preferable.
In the present invention, the weight average molecular weight of the styrenic block copolymer is measured by a gel permeation chromatography (GPC) method.

  The styrenic block copolymer is not particularly limited as long as it is conventional for gels. The styrenic block copolymer of the present invention includes a hydrogenated product of a styrenic block copolymer.

The styrenic block copolymer includes, as a hard segment, for example, one or more types such as a polystyrene segment or a poly (α-methylstyrene) segment; as a soft segment, for example, polybutadiene, hydrogenated polybutadiene, polyisoprene or It is a block copolymer composed of one or more kinds such as hydrogenated polyisoprene, and is either a diblock copolymer, a triblock copolymer having a polystyrene segment constituting a terminal portion or a multiblock copolymer. It may be present alone or in a mixture of two or more.
In order to give the gel high elasticity and excellent mechanical strength, it is preferable to use a polystyrene segment as the hard segment and a polyisoprene segment as the soft segment.

Examples of the styrene block copolymer of the present invention include styrene butadiene styrene block copolymer (SBS), styrene ethylene butylene styrene block copolymer (SEBS), styrene isoprene butylene styrene block copolymer (SIBS), and styrene isoprene. Styrene block copolymer (SIS), styrene ethylene propylene styrene block copolymer (SEPS), styrene ethylene ethylene propylene styrene block copolymer (SEEPS), etc. can be used. Preferably, a styrene ethylene butylene styrene block copolymer, a styrene ethylene propylene styrene block copolymer, a styrene ethylene ethylene propylene styrene block copolymer, or the like can be used.
In the present invention, one or more of these styrenic block copolymers can be used.

The softener in the present invention is a component that imparts moderate flexibility to the gel.
Examples of the softener include hydrocarbon process oils such as paraffinic process oil, naphthenic process oil and aromatic process oil, and hydrocarbon oils such as liquid paraffin; cottonseed oil, sesame oil, rapeseed oil, large Biogenic fatty acid ester oils such as bean oil, fallen raw oil, palm oil, animal and vegetable oils such as palm oil and olive oil, and dehydrated or hydrogenated fatty acid ester oils obtained by dehydrating or hydrogenating them; and phthalic acid Dibutyl, dioctyl phthalate, di (2-ethylhexyl) phthalate, di (2-ethylhexyl) tetrahydrophthalate, di-n-octyl adipate, di (2-ethylhexyl) adipate, diisodecyl adipate, tricresyl phosphate Such as plasticizers; or mixtures thereof It is below.
In the present invention, the paraffinic process oil is a process oil containing 50% by weight or more of paraffinic hydrocarbons based on the total carbon content, and the naphthenic process oil is the total carbon content of the naphthenic hydrocarbon. The process oil containing 30 to 45% by weight, and the aromatic process oil refers to a process oil containing 35% by weight or more of the aromatic hydrocarbon carbon based on the total amount of carbon.

As a preferred softening agent, the solubility parameter is close to that of a styrenic elastomeric block copolymer, the compatibility with it is excellent, and the viscosity does not cause bleed and is easily mixed into the elastomer. For example, hydrocarbon oil is mentioned.
In hydrocarbon oil, in order to suppress the yellowing and off-flavor of the gel, to improve the safety of the gel to the human body, to improve the dispersibility during kneading, to improve the mechanical properties of the gel, Paraffinic process oil and liquid paraffin are preferred, and those having a high content with respect to the total carbon content of the paraffinic hydrocarbon include, for example, 70% by weight of paraffinic hydrocarbon with respect to the total carbon content and 30 naphthenic hydrocarbons. A paraffinic process oil containing% by weight is more preferred, liquid paraffin is particularly preferred, and high purity liquid paraffin is particularly preferred.
In the present invention, one or more of these softeners can be used.

  The blending amount of the softening agent is not particularly limited as long as the effect of the present invention is not impaired. However, in order to give the gel an appropriate flexibility and excellent elongation, and to prevent bleeding from the gel and contaminating the surroundings, a styrenic Preferably it is 100-900 weight part with respect to 100 weight part of block copolymers, More preferably, it is 100-400 weight part, Especially preferably, it is 100-300 weight part.

In the present invention, it is preferable to use a tackifier so that the amount of the softening agent contained in the gel can be reduced while maintaining the hardness of the gel, and consequently the bleeding of the softening agent can be reduced.
In the present invention, by using a tackifier having a high softening point, the heat resistance of the gel containing the tackifier can be reduced, and the hardness of the gel can be lowered without increasing the amount of the softener. .
In the present invention, the higher the softening point of the tackifier contained in the gel, the more desirable. For example, 125 ° C or higher is preferable, 140 ° C or higher is more preferable, and 150 ° C or higher is particularly preferable.

Examples of the tackifier include terpene resins, coumarone resins, coumarone indene resins, phenol terpene resins, petroleum hydrocarbons, and rosin derivatives. Preferably, a terpene resin is used.
The gel of the present invention can contain one or more of these tackifiers.

  The amount of the tackifier is not particularly limited as long as the effect of the present invention is not impaired, but is usually 10 to 80 parts by weight, preferably 30 to 50 parts by weight with respect to 100 parts by weight of the styrenic block copolymer. More preferably, it is 30 to 35 parts by weight.

In order to further reduce the generation of volatile organic compounds from the gel, it is desirable that the gel of the present invention also contains an antioxidant. As the antioxidant, aromatic amines, phenols, phosphoruss and the like are used. Desirable antioxidants include hindered phenols and phosphites.
For example, t-butylhydroxytoluene (BHT) or pentaerythritol-tetrakis [3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate] is used as the phosphite ester system as the hindered phenol system. , Tris (2,4-di-t-butylphenyl) phosphite and the like.
The gel of the present invention can contain one or more of these antioxidants.

  The blending amount of the antioxidant is not particularly limited as long as the effects of the present invention are not impaired, but is preferably 10 to 20 parts by weight, more preferably 13 to 17 parts per 100 parts by weight of the styrenic block copolymer. Parts by weight.

  In the gel of the present invention, if necessary, a filler such as magnesium carbonate, calcium carbonate, silica, calcium silicate, clay and talc; a colorant such as titanium oxide, iron oxide and an organic pigment; magnesium hydroxide, Flame retardants such as aluminum hydroxide, zinc oxide, zinc carbonate, phosphate esters; lubricants such as paraffin wax can be blended. In addition, a weather resistance imparting agent, an antibacterial agent and the like can be blended.

  The gel of the present invention is prepared by mixing the above-mentioned softener, styrenic block copolymer, and optionally blended components by a mixing means such as a Henschel mixer or a Banbury mixer, and pelletized. It can be produced by any method such as forming into a sheet or rod shape by injection molding, kneading with a twin screw extruder or extrusion while preparing.

  Hereinafter, the present invention will be described in more detail by way of examples. The present invention is not limited by the examples.

Examples 1-9
According to the blending amounts shown in Tables 1 and 2, the gel was prepared by continuous extrusion at 200 ° C. while mixing with a twin screw extruder.

As the styrene block copolymer, SEBS1 (weight average molecular weight of about 300,000) is G1651 (manufactured by Shell Japan Corporation), SEBS2 (weight average molecular weight of about 200,000) is G1654 (manufactured by Shell Japan Corporation), SEBS3 (weight average molecular weight of about 100,000) used G1650 (manufactured by Shell Japan Co., Ltd.).
Moreover, hydrogenated terpene (trade name: Clearon P-150, manufactured by Yashara Chemical Co., Ltd.) as a terpene resin, and Smoyl P-70 (manufactured by Matsumura Oil Research Co., Ltd.) as liquid paraffin A (weight average molecular weight 322), Smoyl P-100 (manufactured by Matsumura Oil Research Co., Ltd.) as liquid paraffin B (weight average molecular weight 357), Smoyl P-260 (manufactured by Matsumura Oil Research Co., Ltd.) as liquid paraffin C (weight average molecular weight 424), Moresco White P-500 (manufactured by Matsumura Oil Research Co., Ltd.) as liquid paraffin D (weight average molecular weight 535) and Moresco White MT-2000 (Matsumura Oil Research Co., Ltd.) as liquid paraffin E (weight average molecular weight 710) Were used respectively.
IRGANOX 1010 (manufactured by Ciba Specialty Chemicals) was used as the antioxidant A, and IRGAFOS168 (manufactured by Ciba Specialty Chemicals) was used as the antioxidant B.

About the gel obtained by said Examples 1-7, hardness, heat resistance, tensile strength, elongation, and adhesiveness were measured by the method as shown below, and the result shown in Table 1 was obtained.
(1) Hardness measurement method:
A gel having a thickness of 10 mm was measured in accordance with JIS K6301 except that an Asker F hardness meter and Asker C hardness meter were used.
(2) Heat resistance: Measurement of compression set: Measured in accordance with JIS K6262 at a test temperature of 70 ° C. and a test time of 22 hours.
(3) Measurement of tensile strength: Measured according to JIS K6301.
(4) Measuring method of elongation: Measured according to JIS K6301.
(5) Measurement of adhesiveness:
The gel produced in the above was cut out to 150 mm × 25 mm to obtain a test piece, and a SUS plate was overlaid on the gel and pressed with a 2 kg roller. Subsequently, after leaving for 17 hours or more, the test piece was peeled from the SUS plate at a peel angle of 90 ° and a test speed of 300 mm / min, and the peel strength at that time was determined.

Measurement of the amount of volatile organic compounds (VOC) generated:
The gels prepared in Examples 8 and 9 were treated at 65 ° C. for 2 hours, and the generated formaldehyde, acetaldehyde, aliphatic straight chain hydrocarbon having 8 to 16 carbon atoms and aliphatic aldehyde having 8 to 12 carbon atoms were generated. The results shown in Table 2 were obtained.
The measurement method was performed according to the Toyota method (TSM 0508G). That is, the gel prepared above was cut into 80 cm ² × 1 mm and sealed in a tedlar pack. Next, curing was performed at 65 ° C. for 2 hours, and then the gas in the Tedlar pack was sampled and subjected to VOC measurement. The aldehydes were measured by high performance liquid chromatography and the aliphatic linear hydrocarbons were measured by gas chromatography-mass spectrum, respectively, and the VOC amount per 1 g of the gel was determined. The detection limit was 0.02 μg / g.

As is clear from Table 1, it was found that increasing the molecular weight of the styrenic block copolymer contained in the gel improves the hardness, heat resistance, mechanical strength, and elongation. Moreover, the gel excellent in heat resistance was also able to be obtained by using the terpene resin of a high softening point.
It was also recognized that the gel surface tackiness can be freely controlled by changing the weight average molecular weight of the paraffinic process oil. In this case, it was confirmed that the larger the weight average molecular weight of the paraffinic process oil, the higher the tackiness and the heat resistance. However, if the weight average molecular weight of the paraffinic process oil is too large, molding becomes impossible. I also understood that.
Furthermore, if the weight average molecular weight of the paraffinic process oil is too small to reduce the tackiness, the heat resistance deteriorated. Therefore, it was recognized that the range of the weight average molecular weight of the paraffinic process oil is important for obtaining good heat resistance.

  From Table 2, it was recognized that the generation of volatile organic compounds was reduced by increasing the molecular weight of the softening agent.

The gel of the present invention is excellent in shock absorption and vibration damping properties, and is useful as a vibration damping material, a vibration damping material, a buffer material or a damper. Especially used for the above applications for OA equipment. Moreover, since it is excellent in tactile sensation and can be formed into a thin and arbitrary shape, it is also useful as a shoe insole, a cushioning material for clothing, or a cushioning material for preventing fracture of the elderly.
In particular, the gel made non-tacky or low-tacky according to the present invention is used to prevent drying of articles used in contact with the human body, such as fish eyes or octopus pain buffer, heel shock absorbers, elbows or heels. It can be applied to pads, scar protection pads, floor slip prevention mats, fish eye or octopus pain cushioning materials, supporters, pumps and other slip prevention materials, foot rubber, or footwear bottom materials.
The gel that has become highly tacky by the method of the present invention is, for example, an anti-slip material or a poultice base material, or an article that is used in contact with the human body, such as a biosensor fixing material or a transdermal drug pad. Can be used for
Furthermore, the gel that reduces the generation of volatile organic compounds by the method of the present invention is an interior material, for example, an interior material for vehicles such as trains, trains, and automobiles, an interior material for indoors, an interior material for ships, or an interior material for airframes, Alternatively, it is useful for articles used in contact with the human body, for example, fish eyes or octopus pain cushioning materials, supporters, anti-slip materials such as pumps, or dry prevention pads such as elbows or heels.

Claims (13)

  A gel comprising a styrenic block copolymer and a softening agent, wherein the softening agent has a weight average molecular weight of 250 or more.   The gel according to claim 1, wherein the styrenic block copolymer has a weight average molecular weight of 250,000 or more.   The gel according to claim 1 or 2, wherein the softening agent is a hydrocarbon oil.   The styrene block copolymer is a styrene ethylene butylene styrene block copolymer, a styrene ethylene propylene styrene block copolymer or a styrene ethylene ethylene propylene styrene block copolymer. gel.   Furthermore, the gel as described in any one of Claims 1-4 containing a tackifier.   Furthermore, the gel as described in any one of Claims 1-5 containing antioxidant.   The gel according to any one of claims 1 to 6, wherein the gel contains a styrenic block copolymer and a softening agent, and the softening agent has a weight average molecular weight of 250 to less than 400.   The gel according to any one of claims 1 to 6, wherein the gel comprises a styrenic block copolymer and a softening agent, and the weight average molecular weight of the softening agent is 400 or more.   The gel according to any one of claims 1 to 6, wherein the gel comprises a styrenic block copolymer and a softening agent, and the weight average molecular weight of the softening agent is 450 or more.   A fish-eye or octopus pain-absorbing material, a supporter, a pumps slip-preventing material, an elbow- or heel-drying pad, a foot rubber or a damper comprising the gel according to claim 7.   An anti-slip material comprising the gel according to claim 8.   The vehicle interior material containing the gel of Claim 9.   A method for controlling the tackiness of a gel containing a styrenic block copolymer and a softener, the method comprising adjusting the weight average molecular weight of the softener.