Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – Process of treating scrap or waste product containing solid...
Reexamination Certificate
2002-02-28
2004-02-03
Cain, Edward J. (Department: 1714)
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
Process of treating scrap or waste product containing solid...
C528S272000
Reexamination Certificate
active
06686399
ABSTRACT:
TECHNICAL FIELD
This invention relates to processes for producing alkyd resins using polyester resins which have been recovered from waste materials such as disused PET bottles and regenerated.
BACKGROUND ART
Heretofore, use of terephthalic acid as the dibasic acid component, which is one of the starting materials of alkyd resins, was more costly than using phthalic acid or phthalic anhydride and the resulting resin was apt to become turbid or develop occurrence of foreign matters. Hence, normally terephthalic acid is not used for alkyd resin production or, if used, in only minor amount. On the other hand, recently disposal of waste is becoming a serious issue and utilization of disused PET bottles by recycling is under study.
A production method of alkyd resins using polyester resins which have been recovered from waste materials such as disused PET bottles and regenerated is described in, for example, Hei 11 (1999)-228733A-JP. Said method comprises subjecting recovered polyester resin and an alkyd resin oligomer having a molecular weight not higher than 5,000 and containing hydroxyl groups to depolymerization and transesterification. However, this method is subject to a number of problems such that it requires advance synthesis of the alkyd resin oligomer, requires many hours for the depolymerization and filtration of ultimately obtained alkyd resin causes occurrence of large amount of filtration residue, because the amount of the alcohol component in the occasion of depolymerization is too low to sufficiently depolymerize the recovered polyester resin.
The object of the present invention is to provide processes for producing transparent alkyd resins which are substantially free of foreign matters and filtration residue within a short time, using the polyester resins which have been recovered from waste materials and regenerated.
DISCLOSURES OF THE INVENTION
We have engaged in concentrative studies with the view to accomplish the above object and now discovered that the object could be fulfilled by conducting depolymerization of said recovered and regenerated polyester resin as dissolved in a mixture or reaction mixture of an alcohol mixture of tetra- or higher hydric alcohol and tri- or lower polyhydric alcohol, or an alcohol component comprising tetra- or higher alcohol, with an oil and fat and/or a fatty acid; and then conducting an esterification reaction by adding a polybasic acid component and if necessary a fatty acid component to the system and come to complete the present invention.
Thus, according to an embodiment of the invention, a process of producing an alkyd resin having an oil length of 30-70% is provided, which is characterized by comprising dissolving a polyester resin, whose chief starting material is terephthalic acid and which has been recovered from waste materials and regenerated, in an alcohol mixture of tetra- or higher hydric alcohol and tri- or lower polyhydric alcohol at a weight ratio as the former/the latter within a range of 0.2-50, depolymerizing the polyester resin in the presence of a depolymerization catalyst, and then adding to the system a polybasic acid component and a fatty acid component to subject them to an esterification reaction, the polyester resin being used in an amount of 5-40% by weight based on the total weight of the polyester resin, the alcohol mixture, the polybasic acid component and the fatty acid component (this process is hereafter referred to as “the first process”).
According to another embodiment of the present invention, another process of producing an alkyd resin having an oil length of 30-70% is provided, which is characterized by dissolving a polyester resin, whose chief starting material is terephthalic acid and which has been recovered from waste material and regenerated, in a mixture or reaction product of an alcohol component containing tri- or lower polyhydric alcohol and tetra- or higher hydric alcohol at a weight ratio of the former/the latter within a range of 0-20, with an oil and fat and/or a fatty acid, depolymerizing the polyester resin in the presence of a depolymerization catalyst, and then adding a polybasic acid component to the system to subject them to an esterification reaction, the polyester resin being used in an amount of 5-40% by weight based on the total weight of the polyester resin, the alcohol component, the oil and fat and/or the fatty acid and the polybasic acid component (“the second process”).
According to the invention, furthermore, paint compositions containing the alkyd resins which are produced by the above first or second process are provided.
Hereinafter the first and second processes of the invention are explained in further details.
EMBODIMENTS OF THE INVENTION
Those polyester resins made chiefly from terephthalic acid, which have been recovered from waste materials and regenerated, and which are used in the first and second processes of this invention (hereafter the polyester resins may be abbreviated as “regenerated PES”) include polyethylene terephthalate (e.g., PET bottles) which are recovered for recycling of resources, industrial waste polyethylene terephthalate, and polyester resins regenerated from the wastes occurring in the course of production of polyester products (film, fibres, automobile parts, electric and electronic parts, etc.) such as polyethylene terephthalate or polybutylene terephthalate made chiefly from terephthalic acid. In particular, recycled polyethylene terephthalate is suitable. The regenerated PES is normally used in the form of chips or pulverized product.
According to the first process of the invention, first such regenerated PES is dissolved in a mixture of a tetra- or higher hydric alcohol and a tri- or lower polyhydric alcohol, and its depolymerization is conducted in the presence of a depolymerization catalyst.
Examples of tetra- or higher hydric alcohols useful in said alcohol mixture include diglycerine, triglycerine, pentaerythritol, dipentaerythritol and sorbitol. Of those, pentaerythritol is particularly suitable because of favorable curing and drying property of the painted film of the paint compositions in which the resulting alkyd resin is used. Also examples of tri- or lower polyhydric alcohols include: trihydric alcohols such as trimethylolpropane, trimethylolethane and glycerine; and dihydric alcohols such as ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, neopentyl glycol, 1,6-hexanediol and 1,4-dimethylolcyclohexane. Of those, glycerine, ethylene glycol, diethylene glycol, triethylene glycol and propylene glycol are particularly suitable, from the standpoints of depolymerization ability as used in mixtures with said tetra- or higher hydric alcohols (e.g., pentaerythritol) and low-temperature dissolving ability of high temperature-melting tetra- or higher hydric alcohols.
In the alcohol mixture, blend ratio of the tetra- or higher hydric alcohol to the tri- or lower polyhydric alcohol is conveniently within a range of 0.2-50, preferably 0.5-35, inter alia, 1-20, in terms of weight ratio of the former/the latter.
The blend ratio of said regenerated PES to the alcohol mixture is within a range of 15/85-80/20, in particular, 20/80-70/30, inter alia, 20/80-60/40, in terms of a weight ratio of the former/latter.
On the other hand, in the second process of the invention, said regenerated PES is dissolved in a mixture of an alcohol. component containing a tetra- or higher hydric alcohol as exemplified in the above as the essential constituent and if necessary a tri- or lower polyhydric alcohol as above-exemplified, with an oil and fat and/or a fatty acid, or in an esterification reaction mixture thereof, and is depolymerized in the presence of a depolymerization catalyst. In this specification, the word “esterification” is used in a sense covering both ordinary estirification reaction and ester- interchange reaction.
In the above alcohol component, convenient blend ratio of tri- or lower polyhydric alcohol to tetra- or higher hydric alcohol is, in terms of t
Ito Kei
Kawamura Chicara
Numa Nobushige
Yoshihara Ichiro
Cain Edward J.
Kansai Paint Co. Ltd.
Wenderoth Lind & Ponack LLP
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