Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – From phenol – phenol ether – or inorganic phenolate
Reexamination Certificate
2000-07-27
2001-12-25
Acquah, Samuel A. (Department: 1711)
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
From phenol, phenol ether, or inorganic phenolate
C528S176000, C528S194000, C528S206000, C528S212000, C528S219000, C528S302000, C528S308000, C528S308600, C524S401000
Reexamination Certificate
active
06333393
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to an aromatic polyester having the following structural units (1) to (5) and a molded article using the aromatic polyester.
wherein Ra, Rb, Rc, Rd, Re and Rf each independently represents a lower alkyl group, lower alkoxy group, phenoxy group, phenyl group or halogen atom, and n represents an integer from 0 to 3.
Conventionally, aromatic polyesters having the above-described structural units (1), (2), (3), (4) and (5) have been known. Particularly, aromatic polyesters which contain industrially easily available structural unit (2) more than diol structural unit (3) are proposed. For example, aromatic polyesters have been proposed in which the ratio of (2)/(3) (=molar ratio of (2) to (3), that is, ratio of number of unit (2) to number of unit (3) in the aromatic polyester. Hereinafter in this specification, each (1), (2), (3), (4) and (5) sometimes refer the structural units (1), (2), (3), (4) and (5), respectively, and the molar ratio of a unit to another unit is indicated by using b “/”.) is 1 or more and 12 or smaller, and (4)/(5) is 0 or more and 1 and smaller (Hereinafter, this aromatic polyester is referred to as “Polyester I”.). Specifically, an aromatic polyester in which (2)1/(3) is 5.00 and (4)/(5) is 0.31 Is disclosed(JP-A-60-38425).
Besides this, as aromatic polyesters having more improved molding property than Polyester I, those in which the ratio of (4)/(5) is 1.04 or more and 19 or smaller, and (2)/(3) is 0.1 or more and 2.67 and smaller has been proposed (Hereinafter, this aromatic polyester is referred to as “Polyester II”.). Specifically, an aromatic polyester in which (2)/(3) is 1.00 and (4)/(5) is 2.33 is disclosed(JP-A-63-57633).
In recent years, since aromatic polyesters are used for electric and electronic components, those which give molded articles having excellent solder temperature resistance and rigidity(flexural elastic modulus) are demanded. However, there are problems that molded articles made from Polyester I exhibit low solder temperature resistance, and Polyester II exhibit low rigidity.
SUMMARY OF THE INVENTION
Under such circumstances, the present inventors have intensively studied to find an aromatic polyester containing unit (2) more than unit (3) and giving molded articles having excellent solder temperature resistance and rigidity. As the results, they have found that an aromatic polyester having a specific composition of (1), (2), (3), (4) and (5) not only has good molding property, but also gives a molded articles having remarkably excellent solder temperature resistance and rigidity. The present invention has thus been completed.
The present invention provides an aromatic polyester having the following structural units, (1), (2), (3), (4) and (5), wherein the amount of the structural unit (1) is 30 to 50based on the total of the all structural units, (2)/(3) Is more than 2.78 and smaller than 4, (4)/(5) is more than 1.0 and smaller than 1.5, and {(2)+(3)}/{(4)+(5)} is from 0.9 to 1.1:
wherein Ra, Rb, Rc, Rd, Re and Rf each independently represents a lower alkyl group, lower alkoxy group, phenoxy group, phenyl group or halogen atom, and l, m, o, p and q each independently represents an integer from 0 to 3.
PREFERRED EMBODIMENT OF THE INVENTION
In the aromatic polyester of the present invention, the structural unit (1) is usually derived from p-hydroxybenzoic acids represented by the following general formula (6):
wherein, each Ra independently represents a lower alkyl group, lower alkoxy group, phenoxy group, phenyl group or halogen atom; 1 represents an integer from 0 to 3; R
1
represents a hydrogen atom or lower acyl group; and R
2
represents a hydroxyl group, lower alkoxy group, phenoxy group or halogen atom.
Examples of the lower alkyl group include a methyl group, ethyl group and propyl group. Examples of the lower alkoxy group include a methoxy group, ethoxy group and t-butoxy group. Examples of the halogen atom include chlorine and bromine. 1 represents an integer from 0 to 3, and an unsubstituted group in which 1 is 0 is preferable
Examples of the lower acyl group include an acetyl group, propionyl group and benzoyl group.
Typical examples of the p-hydroxybenzoic acids include p-hydroxybenzoic acid, methyl p-hydroxybenzoate, ethyl p-hydroxybenzoate, p-acetoxybenzoic acid, methyl p-acetoxybenzoate, ethyl p-acetoxybenzoate, propyl p-hydroxybenzoate, phenyl p-hydroxybenzoate and benzyl p-hydroxybenzoate. Among other, p-hydroxybenzoic acid and p-acetoxybenzoic acrid are preferred.
The structural unit (2) is usually derived from hydroquinones represented by the following general formula (7):
wherein each Rb independently represents a lower alkyl group, lower alkoxy group, phenoxy group, phenyl group or halogen atom; m represents an integer from 0 to 3; and R
3
and R
4
each independently represents a hydrogen atom or lower acyl group. Typical examples of the hydroquinones include hydroquinone and 1,4-diacetoxybenzene.
The structural unit (3) is usually derived from 4,4′-dihydroxybiphenyls represented by the following general formula (8):
wherein Rc and Rd each independently represents a lower alkyl group, lower alkoxy group, phenoxy group, phenyl group or halogen atom: n and each:independently represents an integer from 0 to 3: and R
5
and R
6
each independently represents a hydrogen atom or lower acyl group.
Examples of the 4,4′-dihydroxybiphenyls include 4,4′-dihydroxybiphenyl and 4,4′-diacetoxybiphenyl.
The structural unit (4) is usually derived from terephthalic acids represented by the following general formula (9);
wherein each Re independently represents a lower alkyl group, lower alkoxy group, phenoxy group, phenyl group or halogen atom; p represents an integer from 0 to 3; and R
7
and R
8
each independently represents a hydroxyl group, lower alkoxy group, phenoxy group or halogen atom.
Typical examples of the terephthalic acids include terephthalic acid and dimethyl terephthalate.
The structural unit (5) is usually derived from isophthalic acids represented by the following general formula (10):
wherein, each Rf independently a lower alkyl group, lower alkoxy group, phenoxy group, phenyl group or halogen atom; q represents an integer from 0 to 3; and R
9
and R
10
each is independently represents a hydroxyl group, lower alkoxy group, phenoxy group or halogen atom.
Typical examples of the isophthalic acids include isophthalic acid and dimethyl isophthalate.
In the aromatic polyester of the present invention, the content of the structural unit (1) Is usually from about 30 to 50%, preferably from about 35 to 50% based on the total of the all structural units. In this specification, “%” indicating the content of a structural unit is molar basils, that is, based on the number of the structural unit, not based on the weight of the structural unit, unless otherwise mentioned.
When the content of the structural unit (1) is less than 30%, molding property of the aromatic polyester tends to deteriorate, or rigidity and heat resistance of the molded article made from the polyester tends to drop. When the content of the structural unit (1) exceeds 50%, molding property and solder temperature resistance of the aromatic polyester tends to deteriorate.
In the aromatic polyester of the present invention, (2)/(3) is more than 2.78 and smaller than 4.
When (2)/(3) exceeds the upper limit of the above range, solder temperature resistance of the molded article made from the aromatic polyester tends to drop. When it is not more than 2.78, rigidity of the molded article tends to drop.
In the aromatic polyester of the present invention, (4)/(5) is more than 1.0 and smaller than 1.5.
When (4)/(5) is less than 1.0, rigidity of the molded article made from the aromatic polyester tends to drop. When it is not smaller than 1.5, molding property and solder temperature resistance of the aromatic polyester tends to deteriorate.
In the present invention, {(2)+(3)}/{(4)+(5)} is about 0.9 to 1.1
Acquah Samuel A.
Sughrue Mion Zinn Macpeak & Seas, PLLC
Sumitomo Chemical Company Limited
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