Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – Cellular products or processes of preparing a cellular...
Reexamination Certificate
2002-07-18
2004-11-09
Keys, Rosalynd (Department: 1621)
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
Cellular products or processes of preparing a cellular...
C521S170000, C528S052000, C528S056000, C528S057000, C528S059000, C528S076000, C528S077000, C528S425000, C568S620000, C568S624000
Reexamination Certificate
active
06815467
ABSTRACT:
The present invention relates to methods for producing a polyoxyalkylene polyol and a polymer dispersed polyol. The polyoxyalkylene polyol and the polymer dispersed polyol obtained by the production methods of the present invention are widely used as a material of an elastomer, a synthetic resin, a coating and a sealing material, or as a surfactant, a lubricant, a diluent, a plasticizer, etc. Particularly when they are used as a material for producing a flexible polyurethane foam (hereinafter referred to as flexible foam), a flexible foam having improved mechanical properties such as hardness, moldability, vibrating property and durability can be obtained.
Heretofore, various studies have been conducted to improve properties of a flexible foam. For example, in order to improve comfort of a seat cushion of e.g. an automobile to sit on, improvement of e.g. impact resilience, vibrating property and durability has been desired. Further, in recent years, along with a change in taste of users for comfort to sit on, a flexible foam having a low impact resilience coefficient has been desired. With regard to the vibrating property, it is considered to be effective to make decrement in a frequency region to which human is sensitive (considered to be from 4 to 8 Hz for example, or from 6 to 20 Hz) particularly significant. In order to improve such properties, it is considered to be effective to produce a seat cushion by employing a polyoxyalkylene polyol having a higher molecular weight.
A polyoxyalkylene polyol (hereinafter referred to as polyol) used as a material of a flexible foam is usually produced by subjecting an alkylene oxide such as propylene oxide to ring-open addition polymerization with e.g. a polyhydric alcohol as an initiator by using a sodium type catalyst such as sodium hydroxide or a potassium type catalyst such as potassium hydroxide. By this production method, a monool having unsaturated bonds (unsaturated monool) is formed as a by-product, and the formation amount of the unsaturated monool increases along with decrease in the hydroxyl value (increase in the molecular weight) of the polyol.
In production of a polyol having a hydroxyl value at a level of 56 mgKOH/g which is widely used as a material of a flexible foam, the formation amount of the unsaturated monool is not so large as to be a serious problem. However, in production of a polyol having a high molecular weight and a low hydroxyl value, the formation amount of the unsaturated monool tends to be problematic. In a case where a flexible foam is produced by using a polyol having a high degree of total unsaturation, problems such as decrease in hardness, deterioration of permanent compression set and deterioration of curing property at the time of molding tend to occur. Further, in a case where a polyol having a low hydroxyl value is produced by using a sodium type catalyst or a potassium type catalyst, the degree of total unsaturation tends to be remarkably high, and the production is very difficult.
As a method of producing a polyol having a low degree of total unsaturation and a low hydroxyl value, a production method of subjecting an alkylene oxide to ring-opening addition polymerization by using a double metal cyanide complex as a catalyst is proposed in JP-A-2-276821. Although comfort to sit on remarkably improves when a high molecular weight polyol obtained by this production method is used, there may be a problem in moldability such as air flow, required in addition to comfort to sit on, in some cases. Practically, such a polyol alone is used to produce a flexible foam, degree of closed-cell tends to be relatively high, thus leading to a defect at the time of crushing treatment in some cases.
As a method to overcome the problem of moldability, a method for producing a flexible foam by using as the material a polyol mixture comprising a polyol produced by using a double metal cyanide complex catalyst and a polyol produced by using potassium hydroxide is proposed in JP-A-8-231676. However, in this method, as the polyol produced by using a double metal cyanide complex catalyst, a polyoxyalkylene polyol produced by subjecting propylene oxide alone to ring-opening addition polymerization with an initiator and then subjecting ethylene oxide alone to ring-opening addition polymerization, is used, and further, the degree of unsaturation of the polyol produced by using a potassium hydroxide catalyst is high, and the degree of unsaturation of the entire polyol mixture is thereby high, whereby durability of the foam tends to be insufficient.
Further, as another method, a method of using a double metal cyanide complex catalyst, subjecting a mixture of ethylene oxide with another alkylene oxide to ring-opening addition polymerization reaction system with an initiator to produce a polyol having a random addition structure of ethylene oxide with another alkylene oxide in the molecule of the polyol, and using this polyol to form a flexible foam having favorable moldability, is proposed in U.S. Pat. Nos. 5,605,939 and 5,648,559. However, the present inventors have tried to produce a flexible foam for an automobile seat by using a polyol in Examples as disclosed in the above patents, but a foam could not be produced as depressions (collapses) were formed in the inside and on the surface of the foam.
Under these circumstances, the present invention has been made to overcome the above problems, and it is an object of the present invention to provide methods for producing a material polyol and a polymer dispersed polyol, which provide, in production of a flexible foam using as the material a polyol produced by using a double metal cyanide complex catalyst, a flexible foam having favorable foam moldability maintained, having good physical properties such as hardness and vibrating property, and having favorable durability particularly heat and humidity permanent compression set.
The present invention provides a method for producing a polyoxyalkylene polyol, which comprises subjecting propylene oxide and ethylene oxide to ring-opening addition polymerization with an initiator in the presence of a catalyst, wherein the polyoxyalkylene polyol is a polyoxyalkylene polyol obtained by subjecting propylene oxide to ring-opening addition polymerization with an initiator in the presence of a double metal cyanide complex catalyst to form an oxypropylene block chain, subjecting ethylene oxide and propylene oxide to ring-opening addition polymerization randomly to form an oxyalkylene random chain, changing the catalyst and subjecting ethylene oxide to ring-opening addition polymerization in the presence of an alkali metal catalyst to form an oxyethylene block chain, and the polyoxyalkylene polyol is a polyoxyalkylene polyol having a hydroxyl value of from 5 to 56 mgKOH/g, a proportion of an initiator residue of at most 25 mss %, a proportion of the oxypropylene block chain of from 5 to 50 mass %, a total oxyethylene group content of from 5 to 60 mass %, and a ratio of primary hydroxyl groups among terminal hydroxyl groups of at least 60 mol %.
The present invention further provides a method for producing a polymer dispersed polyol, which comprises polymerizing a monomer having polymerizable unsaturated groups employing the polyoxyalkylene polyol obtained by the above production method as a dispersion medium.
Now, the present invention will be described in detail with reference to the preferred embodiment.
Structure of Polyol (1)
The polyoxyalkylene polyol (hereinafter referred to as polyol (1)) of the present invention is a polyoxyalkylene polyol obtained in such a manner that propylene oxide is subjected to ring-opening addition polymerization with an initiator in the presence of a double metal cyanide complex catalyst to form an oxypropylene block chain, ethylene oxide and propylene oxide are subjected to ring-opening addition polymerization randomly to form an oxyalkylene random chain, then the catalyst is changed, and ethylene oxide is subjected to ring-opening addition polymerization in the presence of an alkali metal catalyst to f
Akagi Etsuko
Horie Akio
Sugiyama Kayoko
Toyota Yoshinori
Wada Hiroshi
Asahi Glass Company Limited
Keys Rosalynd
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