Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – From carboxylic acid or derivative thereof
Reexamination Certificate
1999-09-30
2001-08-07
Hoke, Veronica P. (Department: 1714)
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
From carboxylic acid or derivative thereof
C528S280000, C528S285000, C528S286000
Reexamination Certificate
active
06271338
ABSTRACT:
TECHNICAL FIELD
The present invention relates to a polyethylene naphthalenedicarboxylate resin composition and to a bottle which is molded therefrom. More specifically, it relates to a polyethylene naphthalenedicarboxylate resin composition whose molded product is free from the whitening phenomenon and cloudiness and has excellent transparency and good hue although the resin composition has been produced by using a less expensive antimony compound as a catalyst and contains a cobalt compound as a color-controlling agent, and to a bottle which is molded therefrom.
BACKGROUND ART
Polyethylene naphthalenedicarboxylate (hereafter, this may be abbreviated as PEN in some case) is superior in basic physical properties such as heat resistance, gas barrier-property, chemical resistance and the like to polyethylene terephthalate. Because of these merits, polyethylene naphthalenedicarboxylate is increasing its uses as a bottle (container), a sheet material and others in recent years. For these uses, many proposals of blending with polyethylene terephthalate have been made beside the single use of polyethylene naphthalenedicarboxylate.
As for a material to be used for a bottle, especially a beverage bottle, it is strongly required that the material has excellent transparency from the view point of commercial value of a bottle itself or a beverage product.
Polyethylene naphthalenedicarboxylate has a lower crystallization speed than polyethylene terephthalate, and the problem of whitening on blow molding is not so extreme as in polyethylene terephthalate. However, when a certain catalyst composition is used, there is observed a problem of the increasing of the haze of a bottle on molding.
As for catalyst used for producing polyethylene naphthalenedicarboxylate, a catalyst same as that used for producing polyethylene terephthalate is generally used.
For example, Japanese Unexamined Patent Publication No. 7-258394 (applied as Patent Application No. 6-50250 on Mar. 22, 1994, and opened in an unexamined publication on Oct. 9, 1995) describes a method for obtaining polyethylene naphthalate having excellent transparency with a specific catalyst composition in the presence of an antimony compound.
Japanese Unexamined Patent Publication No. 8-157582 (applied as Patent Application No. 6-331921 on Dec. 8, 1994, and opened in an unexamined publication on Jun. 18, 1996) describes a method for suppressing the occurrence of fine foreign matters by adding a specific nitrogen-containing basic compound in polyethylene naphthalate which uses an antimony compound as a catalyst.
Further, Japanese Unexamined Patent Publication No. 10-245433 (applied as Patent Application No. 9-51636 on Mar. 6, 1997, and opened in an unexamined publication on Sep. 14, 1998) describes a method in which polyethylene naphthalate is obtained by adding trimethyl phosphate as a phosphorous compound in the presence of an antimony compound/a cobalt compound.
The inventors of the present invention have found that it is effective to add a specific phosphorous compound for obtaining polyethylene naphthalate having excellent transparency and hue in the coexistence of an antimony compound/a cobalt compound or under conditions where nitrogen-containing basic compound is absent, and they have reached the present invention.
DISCLOSURE OF THE INVENTION
It is preferred to use a germanium compound as a polycondensation catalyst for producing polyethylene naphthalenedicarboxylate from the view points of hue and crystallization property. However, it is not satisfactory from the view points of cost and catalyst activity.
On the other hand, the use of an antimony compound as a polycondensation catalyst is superior to the use of a germanium compound in the view points of cost and catalyst activity; however, it is inferior to the use of a germanium compound as a polycondensation catalyst in the view points of hue and crystallization acceleration, and in the view point of transparency which will be lowered by the deposition of antimony metal. In this case, the addition of a color-controlling agent such as a cobalt compound or the like with the intention of improving the hue can actually improve the hue, but the transparency is unwillingly decreased. Thus, it has been conventionally difficult to improve both the hue and transparency by adding a color-improving agent such as a cobalt compound or the like.
The object of the present invention is to provide a polyethylene naphthalenedicarboxylate resin composition which is produced by using an antimony compound as a polycondensation catalyst, and a polyethylene naphthalenedicarboxylate resin composition which contains a cobalt compound as a color-controlling agent and which is excellent both in transparency and hue.
Other objects and advantageous points of the present invention will become clear from the following explanations.
The present invention comprises the following constituents.
1. A polyethylene naphthalenedicarboxylate resin composition comprising a polyethylene naphthalenedicarboxylate, an antimony compound, a cobalt compound and a phosphorous compound, in which the phosphorous compound is expressed by the following formula 1, and its acid dissociation constant pKa is not less than 1.0.
2. A polyethylene naphthalenedicarboxylate resin composition described in the constituent 1, wherein the number of deposited particles which are attributable to a catalyst and whose particle sizes exceed 5 &mgr;m is 10 or less per 1 g of the polyethylene naphthalenedicarboxylate resin composition.
3. A polyethylene naphthalenedicarboxylate resin composition described in the constituent 1, wherein the number of foreign matters having particle sizes exceeding 2 &mgr;m is 1000 or less per 1 g of the polyethylene naphthalenedicarboxylate resin composition.
4. A polyethylene naphthalenedicarboxylate resin composition described in the constituent 1, wherein the time needed for filtering 1 g of the polyethylene naphthalenedicarboxylate resin composition according to the method defined in the specification is 100 sec or less.
Hereafter, the present invention will be explained in detail.
<<Polyethylene Naphthalenedicarboxylate>>
Polyethylene naphthalenedicarboxylate is obtained by using a naphthalenedicarboxylic acid as the main dicarboxylic acid component and ethylene glycol as the main diol component.
As for the dicarboxylic acid component, the amount of the main component is 70 mol % or more, preferably 80 mol % or more, of the total dicarboxylic acid components. As for the diol component, the amount of the main component is 70 mol % or more, preferably 80 mol % or more, of the total diol components.
Namely, the polyethylene naphthalenedicarboxylate is allowed to have a dicarboxylic acid component other than the main dicarboxylic acid component in the range of 30 mol % or less, preferably 20 mol % or less, as a copolymerization component, and it is allowed to have a diol component other than the main diol component in the range of 30 mol % or less, preferably 20 mol % or less, as a copolymerization component.
When the copolymerization component of dicarboxylic acid exceeds 30 mol % of the dicarboxylic acid components, or the copolymerization component of diol exceeds 30 mol % of the diol components, the properties characteristic to polyethylene naphthalenedicarboxylate, e.g. gas barrier property and thermal resistance, become poor.
Examples of the naphthalenedicarboxylic acid used as the main component include 2,6-naphthalenedicarboxylic acid and 2, 7-naphthalenedicarboxylic acid.
Examples of the copolymerizable dicarboxylic acid component include aliphatic dicarboxylic acids such as oxalic acid, malonic acid, succinic acid, adipic acid, sebacic acid, dodecanedicarboxylic acid and the like; aromatic dicarboxylic acids such as terephthalic acid, isophthalic acid, diphenyldicarboxylic acid, diphenoxyethanedicarboxylic acid, diphenylsulfonedicarboxylic acid, diphenyletherdicarboxylic acid and the like; alicyclic dicarboxylic acids such as cyclohexanedicarboxylic acid, decalindicarboxylic acid, tetralindicarboxy
Nagano Hiroki
Suzuki Minoru
Yoshida Yoichi
Hoke Veronica P.
Sughrue Mion Zinn Macpeak & Seas, PLLC
Teijin Limited
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