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
1998-10-15
2001-04-17
Seidleck, James J. (Department: 1711)
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...
C524S436000, C524S400000, C524S417000, C524S394000, C524S128000, C524S266000, C523S204000, C525S106000
Reexamination Certificate
active
06218454
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to an acid-resistant, thermoplastic resin composition containing magnesium hydroxide and its molded article. More specifically, the present invention relates to an acid-resistant, thermoplastic resin composition containing a magnesium hydroxide which is surface-treated with at least one compound selected from a water-soluble silane coupling agent, a phosphoric acid ester, a higher fatty acid and an alkali metal salt of higher fatty acid, and a reaction type compatibilizing agent.
PRIOR ART OF THE INVENTION
A halogen-containing flame-retardant for a synthetic resin, which flame-retardant is obtained from an organic halogen compound or a combination of an organic halogen compound and antimony trioxide, has caused a problem socially, since it generates a great deal of smoke and poisonous gases in fire. Therefore, development works for a nonpoisonous flame-retardant containing no halogen have been vigorously made, and magnesium hydroxide has come into effective use. The magnesium hydroxide is required to be incorporated in a higher concentration to some extent as compared with the organic halogen-containing flame-retardant, and the incorporation in high concentration impairs physical properties of a resin. JP-A-54-83952 discloses a magnesium hydroxide having a BET specific surface area of 20 m
2
/g or less and having a BET specific surface area/Blaine permeability method specific surface area ratio in the range of about 1 to 3 as a magnesium hydroxide which does not so much impair physical properties of a resin. Further, magnesium hydroxide has a higher decomposition temperature than aluminum hydroxide so that magnesium hydroxide is not in danger of causing bubbles in a resin molded article at a molding/processing time. Resin molded articles obtained from a resin containing magnesium hydroxide in a high concentration are broadly used for nuclear plants, shipping, offshore oilfields, subways, electric cable servings, communication cables, lags, home electric appliances, office instruments, cars and so on.
However, when these products using magnesium hydroxide as a flame-retardant are subjected to carbonic acid-containing water or acid rain for a long time, the magnesium hydroxide in the thermoplastic resin is dissolved with the acid water so that air holes are generated. Further, a carbonic acid salt, a basic carbonic acid salt, or the like, is generated due to carbon dioxide in the air, and the surface of a resin molded article is whitened, which worsen the appearance of the molded article. It has been found that the so-generated decrease of the magnesium hydroxide concentration causes a problem that flame retardancy which is naturally present is decreased. Furthermore, when the resin-molded article comes into contact with acid agents such as hydrochloric acid or sulfuric acid, the above mentioned corrosion phenomenon occurs remarkably, and, for example, the use in a cable serving for chemical plant is therefore limited.
For overcoming these problems, for example, JP-A-1-245039 discloses a flame-retardant which is obtained by treating the surface of magnesium hydroxide particle with an alkali metal salt of higher fatty acid and then treating it with a sodium salt of boric acid or silicic acid and which is excellent in humidity-resistance, acid-resistance and dispersibility in a resin. Further, JP-A-2-55746 discloses a flame-retardant obtained by surface-treating magnesium hydroxide with a dialcohol amine salt of alcohol phosphoric acid ester or an alkali metal salt.
However, the above flame-retardants are insufficient in acid-resistance against carbonic acid-containing water or acid rain although improved to some extent. For example, the acid-resistance against an acid having a high concentration such as a 36% hydrochloric acid is scarcely improved.
Conventional resin compositions obtained by highly incorporating magnesium hydroxide as a flame-retardant are poor in acid-resistance and resistance against carbonic acid gas. Further, a factory in which a chemical agent is handled requires a resin composition that endures a strong acid, while the conventional resin compositions do not satisfy this requirement. However, there is a strong requirement for a thermoplastic resin composition which inhibits the generation of smoke in fire and which is nonpoisonous and non-halogen. And, there is also a strong requirement for a thermoplastic resin composition which is further able to keep acid-resistance for a long period of time.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide an acid-resistant, thermoplastic resin composition satisfying the above requirements and its molded article.
The present invention provides an acid-resistant, thermoplastic resin composition which contains a thermoplastic resin, 30 to 70% by weight, based on the resin composition, of magnesium hydroxide having a specific surface area of 20 m
2
/g or less, having an average secondary particle diameter of 0.2 to 5.0 &mgr;m and surface-treated with at least one surface-treating agent selected from the group consisting of the following a, b and c,
a. a water-soluble silane-coupling agent
b. a phosphoric acid ester of the formula [2],
[wherein R is an alkyl group or alkenyl group which has 1 to 24 carbon atoms, A is an alkylene group having 2 to 4 carbon atoms, M is an alkali metal, a cation of an alkyl amine having 1 to 4 carbon atoms or a cation of an alkanolamine of the formula [3],
(R′)
3-r
N—(B—OH)
r
(3)
(wherein R′ is a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, B is an alkylene group having 2 to 4 carbon atoms and r is an integer of 1 to 3),
n is an integer of 0 to 6 and m is 1 or 2],
c. a higher fatty acid and/or an alkali metal salt thereof,
and 1 to 20% by weight, based on the resin composition, of a reaction type compatibilizing agent.
Further, the present invention provides an acid-resistant, thermoplastic resin composition obtained by incorporating a magnesium hydroxide which is obtained by surface-treating about 10 to 80%, preferably about 15 to 50%, of the particle surface of magnesium hydroxide having the above specific surface area and the average secondary particle diameter with at least one selected from phosphoric acid ester, a higher fatty acid or an metal salt of higher fatty acid, into a thermoplastic resin in predetermined amounts together with a reaction type compatibilizing agent. Detailed Description of the Invention The present inventors have made various studies for overcoming the above problems and found that acid-resistance of a thermoplastic resin is remarkably improved when a specific magnesium hydroxide and a reaction type comatibilizing agent in predetermined amounts are incorporated into the thermoplastic resin. And the present invention has been accomplished.
The magnesium hydroxide used in the present invention is a magnesium hydroxide whose crystal is grown well and which is free from aggregation. Due to the above features of the magnesium hydroxide, excellent moldability, mechanical strength and flame retardancy are appeared. That is, the magnesium hydroxide used in the present invention is a magnesium hydroxide which has a BET specific surface area of 20 m
2
/g or less, preferably 3 to 10 m
2
/g, and has an average secondary particle diameter of 0.2 to 5.0 &mgr;m, preferably 0.5 to 3 &mgr;m. The magnesium hydroxide may be a synthetic product or a natural product so long as the magnesium hydroxide has the above features.
The silane-coupling agent used in the present invention is a compound of the formula (1),
X—(CH
2
)
n
—Si—(OR)
3
(1)
(wherein X is a vinyl group, an amino group, an epoxy group, etc., R is a methyl group, an ethyl group, a propyl group or &ggr;-methoxyethyl group, n is an integer of 0 to 3 and X is particularly preferably an amino group.)
The surface treatment amount of the silane coupling agent based on the magnesium hydroxide is 0.1 to 3% by weight, preferably 0.3 to 1% by weight. When it is less than
Hiraishi Wataru
Nosu Tsutomu
Tachifuji Tomoko
Asinovsky Olga
Kyowa Chemical Industry Co. Ltd.
Seidleck James J.
Wenderoth , Lind & Ponack, L.L.P.
LandOfFree
Acid resistant, thermoplastic resin composition containing... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Acid resistant, thermoplastic resin composition containing..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Acid resistant, thermoplastic resin composition containing... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2437304