Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – At least one aryl ring which is part of a fused or bridged...
Patent
1988-11-16
1991-12-31
Page, Thurman K.
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
At least one aryl ring which is part of a fused or bridged...
524 17, 524 22, 524 28, 524 45, 524 46, 524 47, 524 55, 524492, 524704, C08J 3205, C08J 502, C08K 340, C08L 128
Patent
active
050773364
DESCRIPTION:
BRIEF SUMMARY
FIELD OF THE INVENTION
The present invention relates to low-temperature insulating materials which have excellent flexibility and elasticity at low temperatures.
BACKGROUND OF THE INVENTION
Most of the marketed low-temperature insulating materials utilize gel obtained by adsorbing water in gelatin or water-soluble polymers such as polyvinyl alcohol or polyethylene oxide (see, Japanese Patent Laid Open Publication Nos. 56-36538 and 56-45977). Such gel solidifies too hard at low temperature and lose flexibility at low temperatures. Accordingly, this problem causes an inconvenience when such materials are used as an ice pillow substitute.
Japanese Patent Publication No. 47-18409 discloses oily gels consisting of an unvulcanized elastomeric block copolymer and paraffinic oil. Although flexible, they have a defect of inferior heat-insulating properties.
Japanese Patent Laid Open Publication No. 60-79061 discloses water-containing, water-absorbing cross-linked polymer particles dispersed in a continuous phase consisting of a teleblock copolymer elastomer and oily components, and Japanese Patent Publication No. 60-11738 discloses W/O emulsion obtained by dispersing a water dispersant in a homogeneous dispersing medium containing an oily substance with a high boiling point, natural rubber and synthetic rubber, which is gelled by cross-linking in the presence of a cross-linking agent. Although excellent in heat-insulating properties and flexible at low temperatures, they are associated with complicated processes and high cost. Further, if the amount of water is increased, the mechanical thermal stability will be lost and sometimes water will be found to separate. Moreover, they possess memory effect upon deformation, which is a problem during use.
SUMMARY OF THE INVENTION
The present invention provides low-temperature insulating materials which are inexpensive and have excellent heat-insulating properties and excellent flexibility at low temperatures.
That is, the present invention provides a low-temperature insulating material which comprises (i) polyvinyl chloride, (ii) a plasticizer, (iii) a water-containing or absorbing gel or an aqueous solution of a water-soluble polymer, and (iv) an emulsifier.
Further, the present invention provides a low-temperature insulating material which comprises polyvinyl chloride gelled by mixing with a plasticizer and a surface-covered, water-containing hydrogel.
DETAILED DESCRIPTION OF THE INVENTION
Polyvinyl chloride is an inexpensive industrial material which can be readily obtained. Generally, the average degree of polymerization of polyvinyl chloride is preferably 900-4,000.
As the plasticizer used in the present invention, any one for polyvinyl chloride can be used. Examples of usable plasticizers, includes, for example, di(2-ethylhexyl) phthalate (DOP), dibutyl phthalate (DBP), di(2-ethylhexyl) adipate (DOA), di(2-ethylhexyl) sebacate (DOS), di(2-ethylhexyl) azelate (DOZ), diisodecyl adipate (DIDA), dibutyl sebacate (DBS), epoxydized soybean oil, chlorinated paraffin, a polyester plasticizer and the like. The amount of the plasticizer used is 30-500 parts by weight, preferably 75-200 parts by weight based on 10 parts by weight of polyvinyl chloride. If it exceeds 500 parts by weight, it possesses drawbacks such as deteriorating gel strength. If less than 70 parts by weight, it possesses drawbacks, for example, its fluidity may become worse unless the temperature at ejection is raised.
The water-absorbing gel is a water absorbing high polymer which includes, for example, sodium acrylate polymer, vinyl alcohol - acrylic acid copolymer or isoprene - maleic anhydride copolymer and the like. Instead of the water-absorbing gel, a water-soluble polymer may be used. Examples of such water-soluble polymers includes, for example, carboxymethyl cellulose (CMC), methyl cellulose (MC), polyvinyl alcohol (PVA), sodium alginate, starch, agar, pullulan and the like. The water-absorbing gel or the water-soluble polymer may be added in the low-temperature insulating material as an a
REFERENCES:
patent: 4433020 (1984-02-01), Narukawa et al.
Mitsuba Atsuko
Nagase Tsuneyuki
Nakashio Yukiyasu
Nakashita Takefumi
Sasaki Teruo
Azpuru Carlos
Page Thurman K.
Sumitomo Rubber Industries Ltd.
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