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...
Reexamination Certificate
1999-11-10
2003-03-18
Wu, David W. (Department: 1713)
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...
C524S343000, C524S351000, C524S353000, C524S370000
Reexamination Certificate
active
06534579
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to polyolefin-based compositions having transparency and low water absorption. The invention relates particularly to polyolefin-based resin compositions whose transparency show little decline at a high-temperature/high-humidity atmosphere and fabricated products produced therefrom.
Generally, transparent resins have been used for medical, food, laboratory equipment, optical and other applications as well as for industrial and general-consumer-item applications because it is easy to check the contents of those containers, packaging materials, etc. formed from the resins and it is also easy to carry and process such containers, packaging materials, etc. Specifically, those resins are suitable for use for eyeglass lenses, pickup lenses, f&thgr; lenses and other lenses for optical equipment, and optical recording media such as MO's, DVD's and CD's.
In such applications, these resins are exposed to an atmosphere of high temperature and high humidity in some cases. For example, when the resins are used in containers for food, pharmaceuticals, etc., these containers are subjected to cleaning treatment by use of hot water and steam for the purposes of sterilization. Especially for containers for pharmaceuticals, steam sterilization is normally carried out. Cyclic olefin-based polymer and poly-4-methyl-1-pentene-based resin, which are used for containers for medical and pharmaceutical use to be sterilized with steam because of their excellent heat resistance, rigidity and water vapor resistance as well as their transparency, have suffered a decline in transparency in some cases under some steam sterilization conditions.
Furthermore, when those resins are used for optical products such as optical equipment lenses and optical recording media and products for food and pharmaceuticals packaging applications, such products are placed in a severe environment at high temperature and high humidity in the course of their transportation, among other things, in some cases. In such cases, fine cracks and voids occur in the products probably because the small amount of water having entered the products condensates as the ambient temperature falls. This has caused a loss of transparency of the products in some cases, making the appearance look milk-white. Such decline in transparency in an high-temperature/high-humidity atmosphere is a phenomenon that tends to occur with transparent resins showing low water absorption, and it has been observed with styrene-based polymer, cyclic olefin-based polymer and poly-4-methyl-1-pentene-based resin.
SUMMARY OF THE INVENTION
The objects of the present invention is to provide polyolefin-based resin compositions that show excellent transparency, heat resistance, rigidity and water vapor resistance and suffer little decline in transparency in a high-temperature/high-humidity atmosphere and those polyolefin-based resin moldings obtained from the aforesaid polyolefin-based resin compositions which are suitable for use for optical products and moldings for medical and pharmaceutical use.
Other and further objects, features and advantages of the invention will appear more fully from the following description.
According to the present invention, the polyolefin-based resin composition comprises a polyolefin-based resin having crystallinity of 0% to 20% which shows haze of not more than 10%, total light transmittance of not less than 80%, when measured in accordance with ASTM D1003 using an article 3 mm thick molded therefrom as the test specimen, and water absorption of not more than 0.1% after 100-hour immersion in water at 23° C., and a sorbitol-based derivative which is represented by any of the following general formulas (I-a) to (I-e):
(In the above formulas (I-a) to (I-c), R and R′, each of which may be a same or different, are any of an alkyl group having 1 to 8 carbon atoms, a halogen atom and an alkoxy group having 1 to 4 carbon atoms, and m and n are, each independently of each other, any of integers from 0 to 3.)
(In he above formulas (I-d) and (I-e), R
1
to R
8
are either an aliphatic acyl group having 10 to 30 carbon atoms or a hydrogen atom.)
The aforesaid polyolefin-based resin is preferably at least one of (a) a cyclic olefin-based polymer selected from among the following (A-1), (A-2), (A-3) and (A-4) and (b) a polycyclohexane-based resin:
(A-1): An a-olefin-cyclic olefin random copolymer obtained by copolymerizing the a-olefin having 2 to 20 carbon atoms and the cyclic olefin represented by the following formula (II) or (III):
(In the above formula (II), n is 0 or 1, m is integers of 0 or a number not less than 1, q is 0 or 1, R
1
to R
18
and R
a
and R
b
are, each independently of each other, a hydrogen atom, a halogen atom or a hydrocarbon group, and R
15
to R
18
may be bonded with each other to form a monocyclic or polycyclic ring, while the said monocyclic or polcyclic ring may have a double bond or R
15
and R
16
, or R
17
and R
18
, may form an alkylidene group.)
(In the above formula (III), p and q are integers of 0 or a number not less than 1, m and n are 0, 1 or 2, R
1
to R
19
are, each independently of each other, a hydrogen atom, a halogen atom, an aliphatic hydrocarbon group, an alicyclic hydrocarbon group, an aromatic hydrocarbon group or an alkoxy group, while the carbon atom to which R
9
and R
10
are attached and the carbon atom to which R
13
or R
11
is attached may be bonded directly or via an alkylene group having 1 to 3 carbon atoms and, when n=m=0, R
15
and R
12
, or R
15
and R
19
, may be bonded with each other to form a monocyclic or polycyclic aromatic ring.)
(A-2): A ring-opening polymer or copolymer of the cyclic olefin represented by the above formula (II) or (III).
(A-3): A hydride of the ring-opening polymer or copolymer of (A-2) above.
(A-4): A graft-modified material of (A-1), (A-2) or (A-3) above.
Furthermore, the polyolefin-based resin composition of the present invention comprises a polyolefin-based resin comprising at least one of the cyclic olefin-based polymers selected from among the group comprising the following (A-1), (A-2), (A-3) and (A-4) and a sorbitol-based derivative represented by the above general formulas (I-a) to (I-e).
The present invention provides polyolefin-based resin moldings formed from the aforesaid resin composition, which are suitable for use for optical products and moldings for medical and pharmaceutical use.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
The polyolefin-based resin composition comprises a polyolefin-based resin having transparency and low water absorption and a particular sorbitol-based derivative. First, an explanation is given of the polyolefin-based resin.
Polyolefin-based Resin:
The polyolefin-based resin used in the present invention is composed mostly of carbon atoms and hydrogen atoms and has such transparency that the haze is preferably not more than 10%, more preferably not more than 5%, the total light transmittance is normally not less than 70%, preferably not less than 80%, more preferably not less than 85% when measured in accordance with ASTM D1003 using an article 3 mm thick molded therefrom as the test specimen, and the water absorption is preferably not more than 0.1% after 100-hour immersion in water at 23° C. Moreover, in the present invention, for the polyolefin-based resin, low-crystallinity or non-crystalline polyolefin-based resins are preferable in that they show excellent transparency, and the crystallinity as measured by X-ray diffractometry is preferably 0% to 20%, more preferably 0% to 10%, much more preferably 0% to 2%, most preferably 0%.
Examples of the aforesaid polyolefin-based resin include cyclic olefin-based polymer, polycyclohexane-based resin, and in addition those resins which have a hydrophilic functional group such as the hydroxyl group, ester group, carbonyl group and amide group in its basic skeleton consisting of carbon atoms and hydrogen atoms, while the content of such functional group is low and the water absorption
Nishijima Shigetoshi
Yamamoto Yohzoh
Birch & Stewart Kolasch & Birch, LLP
Harlan R.
Mitsui Chemicals Inc.
Wu David W.
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