Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – Processes of preparing a desired or intentional composition...
Reexamination Certificate
1996-01-05
2002-01-29
Hoke, Veronica P. (Department: 1714)
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
Processes of preparing a desired or intentional composition...
C524S153000, C524S291000, C524S302000
Reexamination Certificate
active
06342549
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to cycloolefin resin pellets comprising cycloolefin resin pellets and a coating material adhered onto the surface of the pellets, and a process for producing a molded product thereof. More particularly, the present invention relates to cycloolefin resin pellets making it possible to reduce the amount of impurities, such as gelatinous contaminants and burns, which are adversely affected to the transparency of a molded product when producing by melting the pellets of a cycloolefin random copolymer of ethylene and a specific cycloolefin, a ring-opening (co)polymer of the specific cycloolefin and a hydrogenation product of the ring-opening (co)polymer; and a process for producing a molded product thereof.
BACKGROUND OF THE INVENTION
The present inventors have proposed a variety of cycloolefin random copolymers of ethylene and a specific cycloolefin, as described in, for example, Japanese Patent Laid-Open Publication No. 168708/1985 and specifications of Japanese Patent Applications No. 220550/1984, No. 236828/1984, No. 236829/1984 and No. 242336/1984. The cycloolefin random copolymers described in those specifications have excellent transparency and are excellent in various properties such as heat resistance, thermal aging resistance, chemical resistance, solvent resistance, dielectric properties and mechanical properties. Further, such cycloolefin random copolymers have good adhesion to substrates of various materials. Accordingly, the cycloolefin random copolymers can be used, for example, in a field of optical materials such as optical memory discs and optical fibers, and a field of transparent container materials and packaging materials such as transparent films and transparent containers. Moreover, since the ring-opening (co)polymer of the above-described cycloolefin and the hydrogenation product thereof have similar properties to the cycloolefin random copolymer, these have been used for the same application field.
In general, such cycloolefin resins are pelletized immediately after the copolymerization, and the resultant pellets are melted to form a molded product, such as films, sheets and injection molded products.
However, when a variety of molded products are formed from these cycloolefin resin pellets, the transparency is sometimes reduced due to the production conditions.
The present inventors have studied about the reason for undesirably reducing the transparency, and as a result, they have found that the reduction of the transparency is caused by impurities, such as gelatinous contaminants and burns, generated in the cycloolefin resin.
That is, since the cycloolefin resin pellets can be prepared immediately after producing a resin under the conditions such that an excess shear stress is not applied to the resin, the amount of gelatinous contaminants contained therein are very small, as described hereinafter. However, it has been found that the gelatinous contaminants in the molded product formed from such pellets are liable to markedly increase as compared to the pellets used as a starting material, causing to the reduction of the transparency.
For reducing the amount of the impurities generated in the molded product, an antioxidant and the like are generally incorporated into the polymer. However, even if such antioxidants are incorporated as a stabilizer, the amount of the impurities in the molded product can be reduced only to a limited amount.
OBJECT OF THE INVENTION
Accordingly, an object of the present invention is to provide cycloolefin resin pellets capable of producing a molded product having excellent transparency, and a process for producing a molded product thereof.
SUMMARY OF THE INVENTION
The cycloolefin resin pellets of the present invention comprises a cycloolefin resin pellet and a powdery coating material and/or a liquid coating material, the melting point or the glass transition point of said coating material being 200° C. or lower, the coating material being adhered onto the surface of the pellet comprising at least one cycloolefin resin selecting from:
(A) a cycloolefin random copolymer of:
(a) ethylene and
(b) a cycloolefin represented by the following formula (I) or (II) and having a softening temperature (TMA) of 70° C. or higher;
(B) a ring-opening (copolymer of a cycloolefin represented by the following formula (I) or (II) and having a softening temperature (TMA) of 70° C. or higher; and
(C) a hydrogenation product of the ring-opening. (co)polymer (B) and having a softening temperature (TMA) of 70° C. or higher;
wherein n is 0 or 1; m is 0 or a positive integer; q is 0 or 1;
R
1
to R
18
, and R
a
and R
b
are each independently a hydrogen atom, a halogen atom and a hydrocarbon group;
R
15
to R
18
may be linked with one another to form a monocyclic or polycyclic ring which may have a double bond; and
R
15
and R
16
, or R
17
and R
18
may together form an alkylidene group; or
wherein each of p and q is independently 0 or an integer of 1 or more; each of m and n is independently 0, 1 or 2;
R
1
to R
19
are each independently a hydrogen atom, a halogen atom, an aliphatic hydrocarbon group, an alicyclic hydrocarbon group, an aromatic hydrocarbon group or an alkoxy group; the carbon atom to which R
9
and R
10
are linked may be bonded directly or by way of an alkylene group of 1 to 3 carbon atoms to the carbon atom to which R
13
is linked or the carbon atom to which R
11
is linked; and
R
15
and R
12
, or R
15
and R
19
may be linked to each other to form a monocyclic or polycyclic aromatic ring when each of m and n is 0.
The process for producing a molded product of the cycloolefin resin pellets of the present invention comprises the steps of:
adhering onto the surface of 100 parts by weight of a cycloolefin resin pellet, 0.01 to 10 parts by weight of a powdery coating material and/or a liquid coating material, the melting point or the glass transition point of the coating material being 200° C. or lower, and
melting the resultant pellet to form a molded product,
the cycloolefin resin pellet comprising at least one cycloolefin resin selecting from:
(A) a cycloolefin random copolymer of:
(a) ethylene and
(b) a cycloolefin represented by the following formula (I) or (II) and having a softening temperature (TMA) of 70° C. or higher;
(B) a ring-opening (co)polymer of a cycloolefin represented by the following formula (I) or (II) and having a softening temperature (TMA) of 70° C. or higher; and
(C) a hydrogenation product of the ring-opening (co)polymer (B) and having a softening temperature (TMA) of 70° C. or higher.
In the present invention, the molded product is usually produced by pelletizing the cycloolefin resin in a powdery state to obtain pellets, adhering a specific powdery coating material and/or a liquid coating material onto the surface of the pellets, and melting the resultant pellets to form a molded product, so that impurities such as gelatinous contaminants or burns are hard to be generated at the time of molding. Therefore, when by the use of the process according to the present invention, optical disc substrates are manufactured, reading errors caused by the impurities in the substrate can be reduced. Further, when a transparent film is formed, a film having an extremely high transparency can be obtained.
DETAILED DESCRIPTION OF THE INVENTION
The cycloolefin resin pellets of the present invention and the process for producing a molded product thereof will be described in detail hereinafter.
The molded product of the cycloolefin resin pellets according to the present invention is produced by adhering a specific powdery coating material and/or a specific liquid coating material onto the surface of a cycloolefin resin pellet, and melting the resultant pellet to form a molded product.
The cycloolefin resin used in the present invention is selected from:
(A) a cycloolefin random copolymer of:
(a) ethylene and
(b) a cycloolefin represented by the following formula I) or (II) and having a softening temperature (TMA) of 70° C. or higher;
(B) a ring-opening (co)polymer of a c
Hirose Toshiyuki
Kimura Toshio
Osato Shinji
Yamamoto Yohzoh
Hoke Veronica P.
Mitsui Chemicals Inc.
LandOfFree
Cycloolefin resin pellets and a process for producing a... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Cycloolefin resin pellets and a process for producing a..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Cycloolefin resin pellets and a process for producing a... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2857802