RU2228341C2 - Method of manufacturing methyl methacrylate-based organic glass - Google Patents

Abstract

FIELD: polymer materials. SUBSTANCE: method comprises polymerization and/or copolymerization of methyl methacrylate to a certain conversion followed by orientation. According to invention, polymerization and/or copolymerization is conducted until conversion 50-98% is attained and, after orientation, additional polymerization to conversion close to 100% is performed. Organic glass thus obtained shows higher (up to 160 C and higher) working temperature, decreased shrinkage at temperature above vitrification temperature, and elevated impact resistance. EFFECT: improved performance characteristics. 7 cl, 1 tbl, 7 ex

Description

The invention relates to methods for producing organic glass, in particular, based on methyl methacrylate.

A known method of producing organic glass based on methyl methacrylate, including the polymerization and / or copolymerization of methyl methacrylate to a specific conversion (Gudimov MM, Perov BV, Organic glass. - M., Chemistry, 1981 [1]). According to this method, the polymerization of methyl methacrylate is carried out to a conversion close to 100%, and then the resulting product is oriented. Get organic glass, known under the brand name AO-120. This glass has insufficient operational properties for a number of applications, in particular, its operating temperature is not higher than 80 ° C. With some types of increased loads, glass is fragile.

Closest to the proposed is a method for producing organic glass based on methyl methacrylate, including the polymerization and / or copolymerization of methyl methacrylate, orientation and additional polymerization of the obtained product (RU 2073609 C1 [2]).

In this method, the orientation of glasses with a conversion of 92-96% is carried out at temperatures exceeding the glass transition temperature of 100% organic glass (110-120 ° C for PMMA). In the process of orientation, the residual monomer is depolymerized.

This method requires orientation at relatively high temperatures, which puts forward increased demands on the equipment used; the method does not allow to achieve high degrees of drawing, which ultimately limits the operating temperature of the final product to values close to those characteristic for the products obtained in [1].

The task was to develop a method for creating organic glass based on methyl methacrylate, which provides

- the ability to reduce the orientation temperature of organic glass in comparison with known methods;

- increasing the degree of extraction of high molecular weight product,

- increase the temperature of operation of the final material.

This problem was solved by the present invention. In the method for producing organic glass based on methyl methacrylate, including the polymerization and / or copolymerization of methyl methacrylate, the orientation and additional polymerization of the obtained product, according to the invention, after the polymerization and / or copolymerization of methyl methacrylate before the conversion of 50-98%, the obtained product is oriented and, after orientation, additional polymerization is carried out up to a conversion close to 100%.

The orientation is preferably carried out by hood up to 50-180% at a temperature above the glass transition temperature of the product subjected to hood.

Additional polymerization is preferably carried out at 110-170 ° C.

Additional polymerization can also be carried out at a temperature below the glass transition temperature of the product, for example by photoinitiation.

The copolymerization of methyl methacrylate is preferably carried out with bi - or polyfunctional monomers.

At least one of the monomers selected from the group including diallyl adipate, allyl methacrylate, triallyl isocyanurate, allyl methacryl ether, allyl methacryl ether diethylene triethylene ether, diethylene glycol triethyl ether, diethylene triethylene ether isophthalic acid.

In this case, at least one of the monomers selected from the group consisting of diallyl isophthalate, monoethylene glycol dimethacrylic ester and allyl methacrylate is preferably used.

In the subsequent part of the description, the relationship of the features of the claims with the technical effect achieved by the invention is disclosed.

Upon receipt of organic glass, the orientation can be carried out by various methods, for example by drawing.

In the production of glass AO-120 [1], the degree of drawing is reached up to 60-80%. A further increase in the hood does not lead to an improvement in physical and mechanical characteristics and operational properties. Glass becomes fragile. However, if the polymerization and / or copolymerization of methyl methacrylate is carried out before the conversion of 50-98%, and not up to 100%, as in [1], then the remaining part of the free monomer after its polymerization, following the orientation of the polymerized part of the monomer, will lead to the formation of a certain non-oriented “ matrix ”, as if enveloping an oriented part of the product, and such a matrix strengthens the oriented part, and with it the entire product, reduces the possibility of fragility. This allows orientation to higher degrees, of the order of 120-180%, without compromising performance. This leads to an improvement in a number of properties of the final product, in particular, to an increase in the operating temperature to 120 ° C (table, glasses 1 and 2) and to a decrease in shrinkage when heated above the glass transition temperature.

If copolymerization of methyl methacrylate and bi- or polyfunctional monomers occurs, the aforementioned non-oriented “matrices”, as if enveloping the oriented part of the product, will be crosslinked to a certain extent, which further increases the operational characteristics of the final product, in particular, increases the operating temperature to 160 ° C (table , glass 4 and 5), and the almost complete disappearance of shrinkage when heated above the glass transition temperature.

The possibility of implementing the described invention is illustrated by the following example.

Example 1

The following compounds were used as starting products for the preparation of organic glasses:

a) monomers: methyl methacrylate (MMA), diallyl adipate (DAAD), allyl methacrylate (AMA), triallyl isocyanurate (TAIC), monoethylene glycol allyl methacrylate (GAM), diethylene glycol (tialamide diallyl glycol) (diethylglycol) monoethylene glycol dimethacrylic ester (DMEG), triethylene glycol dimethacrylic ester (TGM-3), tert-butyl peroxymethoxy acrylate (B-3), tert-butyl peroxy isopropoxymethacrylate (B-2), isophthalic acid dimethacrylic ester (Dimethyl acid).

b) initiators: dicyclohexyl peroxydicarbonate (CPC), ditretic butyl peroxide (PTB) was recrystallized from acetone. The content of the basic substance in the initiators was at least 98%.

Allyl methacrylic esters of mono-, di- and triethylene glycol were obtained by reacting methacrylic acid chloride with monoallyl glycol ethers in the presence of triethylamine. Monoallyl ethers of ethylene glycol and diethylene glycol were obtained as a result of the reaction of interaction of ethylene oxide with allyl alcohol, catalyzed by alkaline agents (KOH).

Triethylene glycol monoallyl ether is synthesized from triethylene glycol and allyl alcohol in the presence of aqueous sodium alkali.

The starting materials for the synthesis of peroxide monomer B-2 were β-hydroxymethyl tert-butyl peroxide and acryloyl chloride, and for B-3, β-hydroxypropyl peroxide and methacryloyl chloride. The reaction was carried out in chloroform in the presence of copper. The content of the basic substance is not lower than 96-98% by active oxygen.

Samples of organic glasses of various formulations were obtained by polymerization and copolymerization of the initial reaction mixture in bulk in silicate glass forms. To compose the forms, silicate glass trichloromethylsilane silicate glass with a contact angle of 50-60 ° was used.

The polymerization process was carried out in 2 stages. At the first stage, polymerization was carried out in the presence of an initiator, dicyclohexyl peroxydicarbonate in an amount of 0.6 parts by weight. for glasses 4 mm thick in a water bath at 20 °. In this case, the achieved conversion was 50-98%. The second stage of the process (depolymerization) was carried out in an air cabinet according to the regime: raising the temperature to 115 ° for 3 hours, holding at 115 ° for 3 hours, cooling to 40 ° for 3 hours. According to IR spectroscopy, the content of unreacted MMA in the studied copolymers was less than 1%.

The orientation of the product after the first polymerization stage was carried out by compressing or stretching the sample.

Orientational deformation was carried out at a clamping speed of 10 mm / min in the temperature range corresponding to its greatest deformability,

To refine the technological parameters of orientation during biaxial extraction of polymerizates with incomplete conversion under experimental production conditions and to obtain samples of large (1000 × 1000 mm) sizes, an experimental setup was made. It consists of the following main nodes:

1) frame assembly;

2) air heating system;

3) cover;

4) the hydraulic cylinder lifting the cover;

5) service platform;

6) the control panel of the workplace;

7) hydrostation 12/12 G 48-12.

The installation is mounted on a rigid welded frame located on four racks. Along the perimeter of the frame are 24 worm gears, through which 24 lead screws pass through the hub of the worm wheel. Clamps are attached to the lead screws in the chamber: 12 main and 12 auxiliary. Using 12 main clamps, it is possible to orient the workpiece having an initial size of 400 × 400 mm. Auxiliary clamps can be used with a minimum glass size of 750 × 750 mm. Clamping speed 23 mm / min.

The manufactured installation differs from industrial orientation installations in that the clamps can be heated by supplying hot water before starting the orientation hood. This is necessary to ensure the polymerization of glass with incomplete conversion in the clamps before stretching, which allows their further deformation. This, in particular, allows the orientation of the product in the clamps to be heated to the glass transition temperature of the product before orientation, in order to further polymerize this part by transferring heat from the clamps to the product.

In industrial installations, unlike the proposed experimental clamps, they are equipped with water cooling so that in places where tensile forces are applied, the polymer remains in a glassy state.

Orientation was carried out by drawing on 50-180%. The properties of the obtained glasses are shown in the table.

As can be seen from the table, the operating temperature of the glasses obtained according to this invention (glasses 1-5) is higher than the known glasses oriented according to the classical method (AO-120).

Example 2

A sheet of polymethylmethacrylate with a conversion of 50% was obtained according to example 1. As the initiator, CPA was used in an amount of 0.6 parts by weight. The glass transition temperature of the obtained product was -10 ° C. The orientation of the product was carried out by stretching at 20 ° C to a degree of drawing 180%. The depolymerization of oriented organic glass was carried out directly in the clamps of the orientation apparatus of Example 1 at a temperature of 115 ° C, after which the oriented sheet was removed from the clamps. The content of unreacted MMA was less than 1%. Operating temperature 150 ° C.

Example 3

A sheet of polymethyl methacrylate with a conversion of 98% was obtained according to Example 1. PTB was used as an initiator. The glass transition temperature of the obtained product was 90 ° C. The orientation of the product was carried out by stretching at 110 ° C to a degree of drawing 60%. The depolymerization of oriented organic glass was carried out directly in the clamps of the orientation apparatus of Example 1 at a temperature of 170 ° C, after which the oriented sheet was removed from the clamps. The unreacted MMA content was less than 1%. Operating temperature 125 ° C.

Example 4

A sheet of polymethyl methacrylate with a conversion of 80% was obtained according to example 2. The glass transition temperature of the obtained product was 20 ° C. The orientation of the product was carried out by stretching at 45 ° C to a degree of drawing 120%. The depolymerization of oriented organic glass was carried out directly in the clamps of the orientation apparatus of Example 1 at a temperature of 125 ° C, after which the oriented sheet was removed from the clamps. The content of unreacted MMA was less than 1%. Operating temperature 140 ° C.

Example 5

A sheet of polymethyl methacrylate with a conversion of 85% was obtained according to Example 1. A mixture of CPA and azobisisobutyronitrile was used as an initiator. The glass transition temperature of the obtained product was 50 ° C. The orientation of the product was carried out by stretching at 75 ° C to a degree of drawing 120%. The depolymerization of oriented organic glass was carried out directly in the clamps of the orientation unit by irradiating a DRSh-250 lamp with UV light at 20 ° C, after which the oriented sheet was removed from the clamps. The content of unreacted MMA was less than 1%. Operating temperature 140 ° C.

Example 6

A sheet of a MMA-DMEG copolymer with a 50% conversion was obtained according to Example 1. The glass transition temperature of the obtained product was -10 ° C. The orientation of the product was carried out by stretching at 20 ° C to a degree of drawing 180%. The depolymerization of oriented organic glass was carried out directly in the clamps of the orientation apparatus of Example 1 at a temperature of 115 ° C, after which the oriented sheet was removed from the clamps. The content of unreacted monomers was less than 1%. Operating temperature 150 ° C.

Example 7

A sheet of a MMA-DMEIF copolymer with a 50% conversion was obtained according to Example 1. The glass transition temperature of the obtained product was -10 ° C. The orientation of the product was carried out by stretching at 20 ° C to a degree of drawing 180%. The depolymerization of oriented organic glass was carried out directly in the clamps of the orientation apparatus of Example 1 at a temperature of 115 ° C, after which the oriented sheet was removed from the clamps. The content of unreacted monomers was less than 1%. Operating temperature 145 ° C.

Claims (7)

1. A method of producing organic glass based on methyl methacrylate, including the polymerization and / or copolymerization of methyl methacrylate, orientation and additional polymerization of the obtained product, characterized in that after polymerization and / or copolymerization of methyl methacrylate before the conversion of 50-98%, the obtained product is oriented, and after orientation carry out additional polymerization to a conversion close to 100%. 2. The method according to claim 1, characterized in that the orientation is carried out by hood up to 50-180% at a temperature above the glass transition temperature of the product subjected to hood. 3. The method according to claim 2, characterized in that the additional polymerization is carried out at 110-170 ° C. 4. The method according to claim 1, characterized in that the additional polymerization is carried out at a temperature below the glass transition temperature of the product, for example, photoinitiation. 5. The method according to claim 1, characterized in that the copolymerization of methyl methacrylate with bi - or polyfunctional monomers. 6. The method according to claim 5, characterized in that at least one of the monomers selected from the group including diallyl adipate, allyl methacrylate, triallyl isocyanurate, allyl methacrylic ether, diethylene glycol glycol, allyl methacrylic ether, diethylene glycol glycol, is used as bi- or poly-functional monomers. monoethylene glycol dimethacrylic ester, triethylene glycol dimethacrylic ester, isophthalic acid dimethacrylic ester. 7. The method according to claim 6, characterized in that at least one of the monomers selected from the group including diallyl isophthalate, monoethylene glycol dimethacrylic ester and allyl methacrylate is used as bifunctional monomers.