JPS6151012A - Production of prepolymer - Google Patents

Abstract

PURPOSE:To obtain a prepolymer of a desired viscosity and excellent storage stability without strict control of polymerzation conditions, by pre-polymerizing diethylene glcyol bisallyl carbonate in the presence of a specified polymerization initator. CONSTITUTION:0.1-2pts.wt. polymerization initiator comprising a peroxide of the formula (wherein R1 is a 1-5C alkyl and R2 is a 4-9C tert. alkyl), e.g., tert-butyloxy pivalate or 2,4,4-trimethylpenyl peroxyneodecanoate, is added to 100pts.wt. diethylene glycol bisallyl carbonate at normal temperature and the mixture is heated to a temperature of 50-100 deg.C to effect is prepolymerization.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a method for producing a prepolymer, particularly a method for producing a prepolymer of diethylene glycol bisallyl carbonate.

(Conventional technology) Diethylene glycol bisallyl carbonate (hereinafter referred to as 0
Polymers of εAC and Kakisu have many excellent properties such as higher impact resistance than inorganic glass, are lightweight, and can be dyed, and are used as materials for various plastic products, especially eyeglass plastics. It is becoming popular as a lens material instead of f@glass.

Conventionally, DBAC polymers have been produced by a method in which a prepolymer is first produced and then main polymerization is carried out, as described below. That is, about 3.3 parts by weight of diisopropyl peroxydicarbonate (hereinafter referred to as IPP) as a polymerization initiator was added to DBAC in an amount sufficient to completely polymerize DBAC throughout the entire polymerization stage. ℃
The resulting prepolymer was injected into a mold held by an elastomer gasket, and the temperature was gradually raised to about 40-105°C over 15-24 hours in an air oven. This is the method of carrying out main polymerization.

In such conventional DBAC polymerization methods, DB
Since the shrinkage of AC during polymerization is large, it is necessary to suppress the shrinkage as much as possible in advance through initial polymerization. Without this initial polymerization step, there would be large gaps or delamination between the mold and the compact, and a polymer product of uniform size would not be obtained. Therefore, the production of prepolymers in the initial polymerization stage is essential for the production of DBAC polymers. In addition, in this method, it is decomposed during the initial polymerization stage and is effective.
The amount of IPP is a small amount of about 3.3 parts by weight IPP. The resulting prepolymer contains a large amount of unreacted IPP.

(Problems to be Solved by the Invention) In the conventional method described above, sufficient amount of IPP is added from the beginning to carry out the initial polymerization and main polymerization consistently, so the following problems occur. there were.

The first problem is that the initial polymerization stage requires strict temperature and time control, and if this is not done, the initial polymerization will proceed to the main polymerization reaction and gelation will occur in the initial polymerization tank, making it impossible to commercialize the product. That would be impossible.

The occurrence of such a situation not only reduces the product yield, but also requires a great deal of time, expense, and labor to dispose of the gelled product and clean the initial polymerization tank, posing a major problem.

The second problem is that production adjustment is difficult.

That is, since the prepolymer contains a large amount of unreacted lPP, it lacks storage stability, and gelation or main polymerization occurs if left at room temperature around 20°C for a long time, so it cannot be stored at room temperature. If it is not possible to do so, and once the initial polymerization has been carried out, it must be cast and main polymerized within a few hours, and if problems such as gelation occur during the casting or main polymerization stage, subsequent main polymerization must be carried out. and the initial polymerization must be stopped. In other words, this results in a significant drop in productivity. In addition, by keeping the initial polymer at an extremely low temperature of about -10°C or less, it is possible to store it for a considerable period of time without gelation or main polymerization, but this requires large-scale refrigeration equipment and is not economical. was disadvantageous.

The third problem is that the amount of IPP added must be strictly controlled. In order to obtain an initial polymer with good storage stability, a method of reducing the amount of IPP, which is a polymerization initiator, may be considered. However, if the amount added is less than 0.1 part by weight, a certain amount of the initial polymer may be present (even if asked, if it exceeds 0.2 part by weight, gelation may easily occur depending on the temperature and time, so the polymerization temperature and time may be changed). In addition to strict control, strict adjustment of the amount of polymerization initiator added was required.

Therefore, in the initial polymerization, there is no need for strict adjustment and control of the amount of polymerization initiator added, temperature, and time, and an initial polymer with the desired viscosity (molecular weight) can be easily obtained and has excellent storage stability. There has been a strong demand for a method for producing an initial polymer.

(Means for Solving the Problem) In order to solve the above-mentioned problem, the present inventors have conducted various experimental studies and found that when a specific amount of a specific peroxide is used instead of IPP as a polymerization initiator. The inventors have discovered that the conventional problems can be solved and have completed the present invention.

In producing a prepolymer of diethylene glycol bisallyl carbonate, the present invention uses the following general formula (where R is an alkyl group having 1 to 5 carbon atoms, and R2 is an alkyl group having 4 to 9 carbon atoms) as a polymerization initiator. This is a method for producing a prepolymer, which is characterized by carrying out initial polymerization using about 0.1 to 2 parts by weight of a peroxide represented by (representing a tertiary alkyl group) based on 100 parts by weight of diethylene glycol bisallyl carbonate.

Type 1 polymerization initiator peroxides include, for example, tertiary butyl peroxy pivalate, tertiary butyl peroxy neohexanoate, tertiary butyl peroxy neodecanoate, tertiary amyl peroxy bivalate, tertiary amyl Peroxyneohexanoate, tertiary amylperoxyneodecanoate), i3) & hexylperoxypivalate, tertiary hexylperoxyneohexanoate, tertiary hexylperoxyneodecanoate, 2.4
．． 4-) U methylpentylperoxypivalet),
2.4.4-) methylpentylperoxyneohexanoate), 2.4.4-)U methylpentylperoxyneodecanoate, and the like.

The amount of Type 1 peroxide used depends on the desired viscosity of the prepolymer and the initial polymerization temperature, or is typically DBAC
The amount is about 0.1 to 2 parts by weight, preferably about 0.3 to 1 part by weight, per 100 parts by weight. If the amount is less than about 0.1 part by weight, the action as a polymerization initiator will be insufficient;
If the amount exceeds parts by weight, the prepolymer tends to gel.

The temperature of the initial polymerization will vary depending on the desired viscosity of the prepolymer and the amount of peroxide used, but is usually about 50
Carry out at a temperature of ~100°C.

The initial polymerization time is about 1 to 3 hours when the initial polymerization temperature is about 50 to 60°C, and about 0.5 hours when the initial polymerization temperature is about 60°C or higher.
5 to 1 hour is appropriate.

In producing a prepolymer by the method of the present invention, the method includes adding and mixing the entire amount of one type of peroxide to DBAC at room temperature, and then raising the temperature to a predetermined temperature for initial polymerization, D
A method is to heat a portion of BAC to a predetermined temperature, and add and mix a solution of peroxide of formula 1 dissolved in the remaining 0BAC, or heat the entire amount of DIEAC to a predetermined temperature, and add peroxide of formula 19 to this. Any known addition-mixing method can be used for producing the prepolymer, such as an addition-mixing method. Immediately or after long-term storage, the prepolymer obtained by the method of the present invention can be converted into the desired polymer by adding a polymerization initiator such as IPP or one type of peroxide, pouring it into a mold, and carrying out mold-curing. (You can ask.

(Examples) Next, the present invention will be explained in more detail with reference to Examples and Comparative Examples. In the examples, all viscosities were measured at 25°C using a B-type viscometer.
It was measured with

Example 1 5 kg of DBAC (viscosity 9 CP) i' and 7.5 g of tertiary butyl peroxy pivalet were added to a four-tube flask with an internal volume of 2β equipped with a stirrer and a thermometer, and the mixture was placed in a constant temperature oil bath at 90°C. The sample was immersed and initial polymerization was carried out for 35 minutes. The viscosity of the obtained prepolymer was 72CP. The viscosity after being left at 20°C for 40 days was 73CP.

Example 2 Initial polymerization was carried out in the same manner as in Example 1, except that tertiary amyl peroxy neohexanoate was used instead of tertiary butyl peroxy pivalate.

The viscosity of the obtained prepolymer was 65CP. 25
The viscosity after standing for 30 days at ℃ was 67CP.

Examples 3 to 5 and Comparative Examples 1 to 2 Tertiary butyl peroxyneodecanoate in the amount shown in Table 1 was added to 1.5 kg of DBAC, and initial polymerization was carried out at 70°C for 1 hour. Viscosity of the obtained prepolymer and 25°C
The viscosity after standing for 45 days was the same (shown in Table 1. However, in Comparative Example 2 (the amount of peroxide added was 2.5 parts by weight), gelation occurred during the initial polymerization.

Table 1 Example 6 1 kg of DBAC was heated to 55°C, and 4.5 g of tertiary hexyl peroxyneodecanoate was added to the DBA.
0.5 kg of C solution was added at once and initial polymerization was carried out for 3 hours.

The viscosity of the treated prepolymer was 180 CP.

The viscosity after being left at 20°C for 15 days was 190 CP.

Example 7 1 kg of DBAC was heated to 80°C, and 2.4.4
0.5 kg of a DBAC solution containing 9 g of -,)limethylpentylberoxyneohexanoate was added, and initial polymerization was carried out for 1 hour. The viscosity of the obtained prepolymer was 90CP. The viscosity after being left at 20°C for 50 days was 90CP.

Comparative Example 3 33 g of diisoprobyl peroxydicarbonate was added to 1 kg of DBAC, and the mixture was immersed in a 45° C. hot water bath for initial polymerization. 40 minutes after the start of initial polymerization, the temperature of the contents began to rise gradually. A rapid increase in viscosity was observed when the temperature of the contents reached 53° C., and the contents gelled after 10 minutes.

Comparative example 4 A prepolymer was produced in the same manner as in Comparative Example 3.

However, when the temperature of the contents reached 50°C, the contents were suddenly cooled down. No gelation occurred and the viscosity was 52CP.

However, when it was left at 25° C. for 7 hours, the viscosity was 220CP, and it turned into a gel after 10 hours. , 1... Comparative example 5.

Initial polymerization was carried out in the same manner as in Comparative Example 3, except that the amount of diisopropyl peroxydicarbonate was changed to 2 g and the polymerization temperature was changed to 70°C. During initial polymerization, the viscosity reached 300 CP after 30 minutes and gelation occurred after 60 minutes.As is clear from Comparative Examples 3 and 4, in the conventional method, strict temperature control is required for initial polymerization, and It can be seen that the storage stability of the prepared prepolymer is also poor.

Furthermore, from Comparative Example 5, it is clear that gelation occurs when the amount of polymerization initiator exceeds 0.2 parts by weight in the conventional method, and it is clear that strict adjustment of the amount of polymerization initiator added is necessary. .

(Effects of the Invention) The method of the present invention does not require strict control of polymerization temperature, polymerization time, and amount of polymerization initiator added during initial polymerization, and can produce a prepolymer having a desired viscosity. In addition, a prepolymer with excellent storage stability can be obtained whose viscosity hardly changes even if it is left at room temperature for several tens of days. Therefore,
No gelation occurs in the initial polymerization tank, and product yield does not decrease.
A great deal of time, expense and labor is not required for the disposal of gelled products and for cleaning the initial polymerization tank. In addition, production adjustment is easy and large refrigeration equipment can be omitted, which is extremely advantageous economically. Furthermore, since it is possible to incorporate a much wider range and larger amount of polymerization initiator into the prepolymer without causing gelation than in conventional methods, there is no need to strictly control the amount of polymerization initiator added; DB
The shrinkage during the main polymerization of AC is small, and therefore it is possible to obtain a highly precise polymer product with much more uniform dimensions than conventional methods.

□１ Therefore, the present invention is extremely useful industrially.

It will be understood that various changes and modifications may be made to the invention without departing from its broader spirit and scope.

Claims (1)

[Claims] 1. Diethylene glycol bisallyl carbonate (D
When producing a prepolymer of EAC), the following general formula ▲mathematical formula, chemical formula, table, etc. are used as a polymerization initiator▼...(I) (In the formula, R_1 is an alkyl group having 1 to 5 carbon atoms, R_
2 represents a tertiary alkyl group having 4 to 9 carbon atoms) is used for initial polymerization using about 0.1 to 2 parts by weight per 100 parts by weight of DBAC. Production method. 2. In the method according to claim 1, the polymerization initiator peroxide is tertiary butyl oxypivalate, tertiary butyl peroxy neohexanoate, tertiary butyl peroxy neodecanoate, tertiary Amylperoxypivalate, tertiary amylperoxyneohexanoate, tertiary amylperoxyneodecanoate, tertiary amylhexyloxypivalate, tertiary hexyloxyneohexanoate, tertiary hexylperoxyneohexanoate selected from the group consisting of decanoate, 2,4,4-trimethylpentylperoxypivalate, 2,4,4-trimethylpentylperoxyneohexanoate and 2,4,4-trimethylpentylperoxyneodecanoate How to be. 3. In the method according to claim 1, DEAC1
About 0.3 to 0.00 parts by weight of peroxide of formula I
Method using 1 part by weight. 4. The method according to claim 1, wherein the initial polymerization is carried out at a temperature of about 50 to 100°C. 5. The method according to claim 4, wherein the initial polymerization is carried out at a temperature of about 50 to 60°C for about 1 to 3 hours. 6. The method of claim 4, wherein the initial polymerization is carried out at a temperature higher than about 60° C. for about 0.5 to 1 hour. 7. In the method according to claim 1, DEAC
A method in which the entire amount of peroxide of formula I is added and mixed at room temperature, and then the temperature is raised to a predetermined temperature for initial polymerization. 8. The method according to claim 1, in which a portion of DEAC is heated to a predetermined temperature, and a solution of peroxide of formula I dissolved in the remaining DEAC is added and mixed for initial polymerization. 9. The method according to claim 1, in which the entire amount of DEAC is heated to a predetermined temperature, and a peroxide of formula I is added and mixed thereto for initial polymerization.