RU2415833C1 - Method of producing styrene oligomers, homologues thereof, methylmethacrylate or mixture of acrylic and methacrylic esters and method of producing composite materials therefrom - Google Patents

Abstract

FIELD: chemistry.

SUBSTANCE: present invention relates to a method of producing oligomers and a method of producing composite materials therefrom. Described is a method of producing styrene oligomers, homologues thereof, methylmethacrylate or mixture of acrylic and methacrylic esters, involving heating a monomer to 70-98°C for 15-60 minutes in the presence of a radical polymerisation initiator in amount of 0.001-0.5 wt % of the monomer until achieving viscosity of 500-2500 mPa·s, and then cooling and adding a polymerisation inhibitor in amount of 0.0005-0.05% of the weight of the monomer. Described also is a method of producing composite materials, characterised by that the oligomer produced using the above described method is mixed with a polymerisation initiator taken in amount of 0.1-4% of the mass of the oligomer and a mineral and/or polymer filler taken in amount of 60-90% of the reaction mass, followed by pressing and/or solidification of the obtained mass at temperature 10-100°C.

EFFECT: shorter oligomerisation time and obtaining an oligomer with longer storage time, obtaining composite material with improved physical-mechanical and technological parametres.

3 cl, 1 tbl, 10 ex

Description

The group of inventions relates to the field of polymer chemistry, namely to the production of oligomers, as well as to building, dental and other composite materials based on them.

In the patent of the Russian Federation No. 2147022, C08F 112/08, publ. 03/27/2000 disclosed a method for producing a film-forming styrene oligomer, which may find application in the preparation of coatings. The method of obtaining a film-forming styrene oligomer by oligomerization at at 20-50 ° C is characterized in that the process is conducted in the presence of 88% H ₂ SO ₄ at a ratio of monomer: acid of 100: 0.2. When the desired conversion of styrene is achieved, toluene in the amount of 10 vol.% Is introduced into the reaction mass, styrene-containing distillate formed in the production of polystyrene by the method of incomplete conversion of the monomer is used as a monomer. The disadvantage of this method is that it uses dangerous concentrated sulfuric acid and a toxic solvent toluene.

In the patent of the Russian Federation No. 2198185, C08F 120/18, C08F 120/36, C08F 120/26, C08F 120/34, C08F 2/00, C07C 69/54, publ. 02/10/2003 describes methods for producing reactive hetero chain oligomers based on proton-containing acrylic derivatives of the general formula CH ₂ = CH — C (O) O- (CH ₂ ) _n —X— [CH ₂ —CH ₂ —C (O) O— (CH ₂ ) _n —X—] _m H, where X is —O—, —OC (O) —N (Ph); n is 2-10; m = 2-15, as well as the method for their preparation by anionic polymerization of acrylic derivatives in the presence of an initiator, moreover, proton-containing acrylic derivatives are taken as monomers, anionic polymerization is carried out in an inert medium in the presence of initiators selected from the group: alkali metals or their derivatives, mixture α-oxide and tertiary amine, the molar ratio of components in which is taken in the range of 0.5-1.5, respectively, the ratio of monomer and initiator being selected from the interval (10-40) ± 1, respectively. But this method requires an inert atmosphere and an initiator of a complex composition.

The closest analogue (prototype) is a method for producing low molecular weight polymethyl methacrylate (RF patent No. 2140931, C08F 120/14, C08F 2/38, publ. 10.11.1999) by radical polymerization of methyl methacrylate in bulk in the presence of an initiating system and hydroquinone, characterized in that as the initiating system, a system containing tributylboron and dicyclohexylperoxydicarbonate is used at a molar ratio of 2: 1 to 10: 1, used in an amount of 1.4-3.6% by weight of the monomer, Hydroquinone is used in an amount of 0.5-3.0 % by weight of monomer, in p the olimerizable mixture is introduced into a regulatory system, which is a mixture of tributylboron with 0.27-0.94% by weight of the monomer of the α, β-unsaturated carbonyl compound at a molar ratio of the unsaturated carbonyl compound and tributylboron from 0.6: 1 to 1.2: one. The invention can be used in the chemical industry to produce molded polymethyl methacrylate for the manufacture of organic glass for various purposes. A significant drawback of the method is the use of an organic solvent, 4-fold freezing of the solution in vacuum, the presence of a scarce and expensive tributylboron catalyst and the process in argon, as well as a long polymerization time (from 4 to 7 hours).

The technical result of the invention is to reduce the oligomerization time and to obtain an oligomer with a long shelf life.

The technical result is achieved by the fact that the method of producing oligomers of styrene, its homologues, methyl methacrylate or a mixture of esters of acrylic and methacrylic acids involves heating the monomer to 70-98 ° C for 15-60 minutes in the presence of a radical polymerization initiator in an amount of 0.001-0.5 % by weight of the monomer to obtain a viscosity of 500-2500 MPa · s, followed by cooling and the introduction of a polymerization inhibitor in the amount of 0.0005-0.05% by weight of the monomer. Polyethylene terephthalate can be added to the initial monomer in an amount up to 10% of its weight.

The method of obtaining oligomers from the group of vinyl monomers, in particular styrene and its homologues, methyl methacrylate or a mixture of esters of acrylic and methacrylic acids with a number average molecular weight of 1 to 20 thousand, is carried out by heating them to a temperature of 70-98 ° C in the presence of radical polymerization initiators (for example, benzoyl peroxide, methyl ethyl ketone peroxide, azo bis isobutyric acid dinitrile, sodium or potassium persulfates) in the range of 0.001-0.5% by weight of the reacting components.

The process itself under these conditions is carried out within 15-60 minutes, which dramatically reduces energy consumption in the production of oligomers. After this process is carried out, a radical polymerization inhibitor (for example, hydroquinone, diphenylol propane, parametoxyphenol, etc.) is introduced into the system of the obtained oligomers in an amount of 0.0002-0.01% by weight of the monomer to prevent further polymerization or to prevent the formation of a solid polymer, i.e. . radical polymerization is carried out until a certain viscosity is reached or a viscous flow state is reached, which allows the product to be transferred to appropriate containers from a working reactor. At the same time, the process is controlled by a rotational viscometer or other types of viscometers, for example VZ-4, according to the expiration time, which is set depending on the desired molecular weight and viscosity of the obtained oligomers: 500-2500 mPa · s.

The method is as follows.

Example 1. In a reactor apparatus with a stirring device, methyl methacrylate, 0.01% benzoyl peroxide or methyl ethyl ketone peroxide is loaded and heated with a steam generator to 90-98 ° C. The process is carried out with continuous stirring for 30-40 minutes until a viscosity of 800 MPa · s and a molecular weight of 15,000 are achieved, controlling the viscosity with a rotational viscometer integrated in the reactor, or periodically taking samples from the reactor, determining the viscosity using the VZ-4 or Stokes method . When the required viscosity is reached, a hydroquinone inhibitor in the amount of 0.01% or bisphenol 0.001%, or para-methoxyphenol 0.005% is introduced into it. The resulting viscous liquid is poured into the dispenser for cooling and packaging. Shelf life of the oligomer is at least 24 months at a temperature not exceeding 20 ° C.

Example 2. In a reactor-apparatus with a stirring device, methyl methacrylate, 0.001% benzoyl peroxide or methyl ethyl ketone peroxide is charged and heated with a steam generator to 90-98 ° C. The process is carried out with continuous stirring for 40-60 minutes until a viscosity of 1200 MPa · s and a molecular weight of 18000 are achieved, controlling the viscosity with a rotational viscometer integrated in the reactor, or periodically taking samples from the reactor, determining the viscosity using the VZ-4 or Stokes method. When the required viscosity is reached, a hydroquinone inhibitor in the amount of 0.01% or bisphenol 0.001%, or para-methoxyphenol 0.005% is introduced into it. The resulting viscous liquid is poured into the dispenser for cooling and packaging. Shelf life of the oligomer is at least 30 months at a temperature not exceeding 20 ° C.

Example 3. Methyl methacrylate, 0.02% benzoyl peroxide or methyl ethyl ketone peroxide, 10% polyethylene terephthalate are charged into a reactor apparatus with a stirring device and heated with a steam generator to 90-98 ° C. The process is carried out with continuous stirring for 30-40 minutes until a viscosity of 2000 MPa · s and a molecular weight of 20,000 are achieved, controlling the viscosity with a rotational viscometer integrated in the reactor, or periodically taking samples from the reactor, determining the viscosity using the VZ-4 or Stokes method. After partial cooling, a polymerization inhibitor is introduced into the oligomer, for example, hydroquinone — 0.01% by weight of the monomer. The resulting viscous liquid is poured into the dispenser for cooling and packaging. Shelf life of the oligomer is at least 18 months at a temperature of no higher than 20 ° C.

Example 4. Styrene and a polymerization initiator — benzoyl peroxide, or methyl ethyl ketone peroxide, or azo-bis-isobutyric acid dinitrile in an amount of 0.5% are loaded into a stirred reactor apparatus. Then the contents of the reactor are heated to 85-95 ° C for 45-60 minutes until a viscosity of 800 mPa · s and a molecular weight of 16,000 are achieved. When the desired viscosity is reached, a hydroquinone inhibitor in the amount of 0.01% or diphenylpropane 0.001%, or parametoxyphenol 0.005% until complete dissolution, after which the oligomer is poured into the dispenser-receiver for cooling and packaging. The resulting oligomer is stored for at least 24 months at a storage temperature of up to 20 ° C.

The second invention relates to a method for producing a composite material from a produced oligomer.

A known method of producing plastic mass (in particular, for denture bases) using acrylic monomers and polymethylmethacrylate, where a long and stepwise polymerization process is used for 6 hours at a catalyst concentration of 0.2-0.3% and a liquid / polymer ratio of 2 / 1,2 (RF patent No. 2237451, A61C 13/01, A61L 27/14, C08F 20/14, publ. 10.10.2004). Obtaining plastic occurs when mixing the product of polymerization with polymer powder in a certain ratio and subsequent swelling, which takes from 2 to 2.5 hours.

The main disadvantage of this method is the length of the process for producing plastics, low impact resistance, wear resistance and heat resistance.

The technical result of the proposed method for producing composite material is to improve the physicomechanical and technological parameters of composite materials, in particular, to increase the compressive, tensile, bending and impact strengths, increase heat and wear resistance, the effects of water and its solutions, reduce the amount of residual monomers in finished products products.

The technical result is achieved in that the method for producing a composite material is characterized in that a polymerization initiator in an amount of 0.1-4% by weight of the oligomer and a filler in an amount of from 60 to 90% of the reaction mass are introduced into the oligomer obtained by the method of the previous invention subsequent pressing and / or curing of the resulting mass at a temperature of 10-100 ° C.

To obtain composite materials, the obtained oligomers are mixed with polymer powders or mineral fillers in an amount of from 60% to 90%. For example, in the case of polymer concrete production, oligomers are mixed with mineral fillers (gravel, sand, gravel, etc.) in a ratio of 1: (4-5). The mixture is thoroughly mixed and poured or syringed into prepared forms, lubricated with release agents, and then pressed and / or cured for 0.2-2 hours at room or elevated temperatures (up to 100 ° C) in order to prevent boiling of residual monomers. Moreover, due to the use of oligomers and pressing, composite materials with improved physical and mechanical properties by 15-25% are obtained.

Similarly, to obtain dental materials, oligomers produced by the method described above are mixed with polymer powders, for example, in the ratio of polymer powder-liquid - (1.5-1.8): 1, which saves expensive powder while reducing toxic content residual monomer due to the fact that the monomer is less in the initial mixture, i.e. due to the use of oligomers, and not monomers as a liquid medium, phase, components. In addition, the values of physical and mechanical indicators increase.

No. Indicators According to the prototype By application one Impact strength, kJ / m ² 10 14-15 2 Water absorption,% 0.051 0.01-0.3 four Heat resistance, ° С 80-85 120 ° C 5 Abrasion, mm ³ / m 1.4-1.5 0.9-1.0

The obtained oligomers can also be used independently or in a mixture with other polymers, oligomers and monomers for the production of paint coatings, composite materials by injection or pressing method, for the manufacture of polymer concrete compositions with various mineral fillers, organic glass of various colors, dental materials with high impact resistance, wear resistance and biological inertness.

Example 5. The oligomer obtained in example 2 is mixed with polymer powders, for example with polymethyl methacrylate in the ratio of powder - liquid (oligomer), equal to (1.8-1.5) -1.0, and polymerization for 20-30 minutes in boiling water and get a new type of dental plastic (for example, for dental prosthesis bases) with the following properties:

Density - 1.2-1.25 kg / m ³ ,

Compression strength - 120-130 MPa,

Tensile strength - 85 MPa,

Flexural strength 130-140 MPa,

Impact strength - 14-15 kJ / m ² ,

Water absorption - 0.3%,

The residual monomer content is 0.1%,

Heat resistance - 120 ° С,

Abrasion - 0.9-1.0 mm ³ / m.

The resulting plastic has improved toxicological (hygienic) indicators by reducing the amount of residual monomer and the use of polyethylene terephthalate.

Example 6. A method of producing a plastic or composite material from an oligomer obtained by the method of Examples 1-3, in which, to carry out the polymerization process at room temperature, a polymerization accelerator is additionally introduced, which is used dimethylaniline - 1%, dimethyl paratoluidine - 0.5%, salts of sulfinic acids — 0.7%; salts of transition metals — 0.5-0.7% by weight of the oligomer. With this method, an oligomer with a shelf life of at least 12 months is obtained. To this oligomer add polymeric (for example, polymethyl methacrylate) and mineral (for example, crushed stone, gravel or sand, etc.) fillers in an amount of up to 90%, the mixtures are thoroughly mixed and poured or syringed and cured for 0.2-2 hours at room or increased to 100 ° C in order to prevent boiling of residual monomers. In this case, composite materials are obtained with a residual monomer content of not more than 0.7%.

Example 7. A method of obtaining a composite material from an oligomer obtained according to examples 1-3, in which building sand, gravel, crushed stone, mineral powder, etc. are taken as a mineral filler. in the amount of 60-90%. The resulting composition is poured into prepared forms, lubricated with a release agent, and incubated until it hardens for 0.5-3 hours, and then the resulting product is removed and incubated until completely cured at temperatures up to 100 ° C. In this case, polymer concrete with the following properties is obtained:

Density - 2.2-2.35 kg / m ³ ,

Compression strength - 120-130 MPa,

Tensile strength - 85 MPa,

Bending strength - 120-140 MPa,

Impact strength - 14-15 kJ / m ² ,

Water absorption - 0.3%,

The residual monomer content is 0.5%,

Heat resistance - 130 ° С,

Abrasion - 0.7-0.8 mm ³ / m.

Example 8. A method of obtaining a composite material from an oligomer obtained according to examples 1-3, into which a polymerization initiator is additionally introduced, for example, benzoyl peroxide in an amount of 3% by weight of the oligomer. As a mineral filler take building sand, gravel, crushed stone, mineral powder, etc. in the amount of 60-90%. The resulting composition is poured into prepared forms, lubricated with a release agent, and incubated until hardening for 0.5-3 hours, and then the resulting product is removed and incubated until completely cured at a temperature of at least 10 ° C. In this case, polymer concrete with the following properties is obtained:

Density - 2.1 -2.25 kg / m ³ ,

Compressive strength - 110-115 MPa,

Tensile Strength - 70-75 MPa,

Bending strength - 100-120 MPa,

Impact strength - 13-14 kJ / m ² ,

Water absorption - 0.3%,

The residual monomer content is 0.5%,

Heat resistance - 120 ° С,

Abrasion - 0.8-0.9 mm ³ / m.

Example 9. In the oligomer obtained in example 3, add 60-75% powder of suspension, emulsion or block polystyrene and mix thoroughly. The resulting mixture is used to obtain various products and foams. At the same time, in the technological process its toxicity is reduced due to a sharp reduction in the amount of volatile monomer and residual monomer after polymerization, the physical and mechanical properties of polystyrene products are improved:

Density - 1050-1070 kg / m ³ ,

Compressive Strength - 100-110 MPa,

Tensile strength - 45-50 MPa,

Bending strength - 80-100 MPa,

Impact strength - 21-22 kJ / m ² ,

Water absorption - 0.01%,

The content of residual monomer, not more than 0.2%,

Heat resistance - 100-105 ° C,

Abrasion - 0.9-1.2 mm ³ / m.

Example 10. In the oligomers obtained in examples 1-3, plasticizers (for example, dibutyl phthalate) are added in an amount of 20%, polymer dispersions (for example, polymethyl methacrylate, polystyrene) in an amount of up to 50%, desiccants (for example, transition metal salts, cobalt naphthenate) , manganese, iron, etc.) in an amount up to 2-3%, pigments (e.g. zinc or titanium white, phthalocyanine dyes, etc.) in an amount up to 40%, corrosion inhibitors (e.g. Trilon B, IFKHAN, OEDFK, etc. .) in an amount up to 5%. The resulting mass is thoroughly mixed and receive paint compositions for various purposes.

Thus, the above examples confirm the achievement of the claimed technical results:

- reducing oligomerization time and obtaining an oligomer with a long shelf life;

- improving the physico-mechanical and technological parameters of composite materials, in particular, increasing compressive, tensile, bending and impact strength, increasing heat and wear resistance, the effects of water and its solutions, reducing the amount of residual monomers in finished products.

Claims (3)

1. A method of producing oligomers of styrene, its homologues, methyl methacrylate or a mixture of esters of acrylic and methacrylic acids, comprising heating the monomer to 70-98 ° C for 15-60 minutes in the presence of a radical polymerization initiator in an amount of 0.001-0.5% by weight monomer to obtain a viscosity of 500-2500 MPa · s, followed by cooling and the introduction of a polymerization inhibitor in an amount of 0.0005-0.05% by weight of the monomer. 2. The method of producing oligomers according to claim 2, characterized in that polyethylene terephthalate is preliminarily introduced into the initial monomer in an amount up to 10% of its weight. 3. A method of producing composite materials, characterized in that the polymerization initiator in an amount of 0.1-4% by weight of the oligomer and a mineral and / or polymer filler in an amount of 60 to the oligomer obtained by the method according to any of claims 1 and 2 are introduced up to 90% of the reaction mass, followed by pressing and / or curing the resulting mass at a temperature of 10-100 ° C.