JPS5838709A - Manufacture of rubber-reinforced styrenic resin - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a new process for producing rubber-reinforced resins, especially ABS resins, which are copolymers of styrenic compounds, acrylonitrile and diolefinic compounds.

It is well known that styrene homopolymers and copolymers of styrene and acrylonitrile have poor impact strength. To increase this impact strength, rubber is added to these styrenic polymers, where it acts as a toughening agent. A widely used method consists of polymerizing styrene in the presence of unsaturated rubber.

The products obtained by this method have superior properties when compared to products produced by other methods, such as compounding or milling.

One common technique for producing rubber-reinforced styrenic resins is to place a homo- or copolymerized system of styrene on the rubber.
By total emulsification method or total suspension method or bulk-suspension method,
It consists of grafting. The technology poses economic problems because the production of these reinforced styrenic resins is dependent on rubber supplies.

In order to reduce the cost of these reinforced styrenic It resins and to eliminate the drawbacks of prior methods, rubber reinforced styrenic resins are produced by forming rubber particles in situ in the presence of hard styrenic resins. A method has been proposed. The method involves contacting a polystyrene matrix with a monomer or mixture of monomers that polymerize to form a rubbery polymer or copolymer, and then suspension-centering the monomers to form a matrix, a rubbery polymer or a copolymer. produces a rubber that is partially grafted to. This method of producing rubber-reinforced styrenic resin is a batch method. Furthermore, the beads obtained by this MM method must be washed, centrifuged, and dried.

Accordingly, there is a need in the art for a relatively inexpensive method of making rubber reinforced styrenic resins.

Accordingly, one object of the present invention is to provide a new method for polymerizing monomers in the presence of a copolymer matrix of styrenic compounds and acrylonitrile.

Another object of the present invention is to provide an improved process for the production of rubber reinforced styrene-acrylonitrile type resins in which the rubber particles are produced in situ by bulk polymerization in the presence of a styrenic resin.

Another object of the present invention is to provide an improved continuous process for bulk polymerizing monomers to form rubbery polymers in the presence of a styrene-acrylonitrile type matrix.

In order to achieve the above objects according to the present invention, a continuous production method of ABS type rubber reinforced styrenic resin is provided,
The method comprises a) continuously feeding into a polymerization zone a mixture obtained by adding a diolefinic compound to a solution of a copolymer matrix of a styrenic compound and acrylonitrile in an inert solvent; b) continuously removing the reaction mixture from the polymerization zone;
It is then subjected to heat treatment to remove residual diolefin compounds and solvents, and recovers the aj ABS resin.

A companion method of the present invention for producing rubber-reinforced styrenic resins comprises adding a diolefinic compound to a solution of a copolymer of styrenic compound and acrylonitrile (i.e., BAN matrix) in an inert solvent; The process consists of carrying out continuous bulk polymerizations of in situ to produce a partially grafted rubbery material on a copolymer matrix.

The copolymer matrix or SAM matrix is
It is a copolymer of a styrene compound and acrylonitrile. Methacrylonitrile can also be used in place of or in admixture with acrylonitrile, and such materials are collectively referred to herein as "acrylonitrile."

The most commonly used styrenic compound for the preparation of copolymer matrices is styrene, but halogen-
Styrene derivatives such as alkyl- and aryl-substituted styrenes may also be used in admixture with styrene. Specific examples of such styrene sieve conductors include methylstyrenes such as evaporative methylstyrene, vinyltoluene, p-chlorostyrene, phenylstyrene, vinylnaphthalene, and the like. As is known in the art, the amount of styrenic polymer optionally used in admixture with styrene can vary within wide limits. In the following description, such materials are collectively referred to as "styrenic compounds."

The amounts of styrenic compound and acrylonitrile in the SAM matrix can also vary within a wide range.

The styrenic compound violet is preferably at least about 10% by weight based on the copolymer, but can reach about 90% and more. Generally, the weight ratio of styrenic compound to acrylonitrile varies between about 4:1 and 1:1.

The 81M matrix is dissolved in an inert solvent that acts as a solvent or at least as a dispersant for the diolefinic compound. The inert solvent has a pressure of about 120 at atmospheric pressure.
C to about 175c, preferably about 130t:' to about 1
It can be a saturated solvent with a boiling point between 50C. Suitable solvents are saturated alkylbenzenes, such as ethylbenzene.

A solution of 81M matrix in an inert solvent can contain from about 10 to about 70% by weight of 81M matrix. The relatively low concentration of the copolymer matrix requires large amounts of solvent to be removed after the production of the ABS resin. On the other hand, diolefinic compounds are not easily soluble or dispersible in viscous solutions with high content in the copolymer matrix.

Preferably, the solution contains about 20 to about 50% by weight copolymer matrix.

The diolefinic compound which forms the rubbery component of the ABS resin upon polymerization is selected from the group consisting of conjugated diolefinic hydrocarbons such as pudadiene, inglen, 2,3-dimethyl-butadiene, chloroprene and mixtures thereof. For economic reasons, butadiene is preferably used for producing the ABS resins of the invention.

According to the method of the present invention, diolefin compounds can be converted into SAN
A rubbery material added to the solution of the matrix and then continuously into the polymerization zone where it is subjected to bulk polymerization conditions to polymerize the diolefinic compound, thereby being dispersed in the matrix in situ. is manufactured.

According to one embodiment of the invention, the polymerization zone consists of two reactors. A solution of SAM Ma) IJ Lux in an inert solvent and a separate portion of the diolefinic compound are added continuously into a first reactor equipped with heating means and a stirrer. The reactor temperature does not exceed about 100C and preferably about 6 (1" to 9
Heat to such a temperature that it is kept within the 0C range. The residence time in the reactor is dependent on the temperature, the concentration of the solution in the BAN matrix and the concentration of the diolefinic compound. These elements not only reach a complete dispersion of the diolefinic compound in the solution of the 81M matrix, optionally with prepolymerization of this compound in the matrix, but also prior to its dispersion into the matrix. selected to avoid premature dimerization of the diolefinic compounds.

The mixture produced in this first reactor is continuously removed and then continuously added to a second reactor for the bulk polymerization of diolefinic compounds. Bulk polymerization is carried out using a free radical initiator, preferably a peroxide, perester or perazo compound, such as tertiary butyl peroxide,
It is carried out in the presence of lauroylnoderoxide, cumyl/f-oxide or azo-bis-isobutyronitrile or mixtures thereof. The amount of such catalyst is between about 0.02 and about 25 weight percent, and preferably between about α05 and about 1.5 weight percent, based on the total weight of monomer and copolymer. can change between This polymerization is about 100-140C
It is carried out at a temperature in the range between .

One suitable method involves using a staged isobaric stirred reactor as the second reactor. Such a reactor is a cylindrical long horizontal vessel with a vertical shaft and a control plate for distribution into each stage, each stage having an agitator attached to the shaft. Each baffle plate is equipped with a top outlet for passing the vaporized gas, which is removed, liquefied, and recycled to the first reactor.

Each baffle plate is equipped with a bottom outlet for passing the polymerization mixture. Regulating means are provided to regulate the pressure, temperature and flow of the mixture during each stage. Polymerization is
It is a progressive multistage polymerization under substantially linear flow and under isobaric conditions.

Polymerization of diolefinic compounds can be carried out using a mixture of two catalysts. The L-type free radical generating catalyst has a short half-life, while the second catalyst has a relatively long half-life. For example, the catalyst system may contain peresters (e.g. tert-butyl-benzoate or tert-buter peracetate) and peroxides (e.g. tert-buternoteroxide, dicumyl-9-oxide or trihydrone-oxide). It may also consist of a mixture. In the first part of the reactor, the polymerization is approximately 10
It is carried out under the action of a perester catalyst at a temperature of 0° to about 1201:'. Complete conversion of the monomers is then carried out in the second part of the reactor at a temperature of about 1201:' to about 140C under the action of another catalyst.

According to another embodiment of the invention, the process can also be carried out by adding only a fraction of the total amount of diolefinic compound into the first reactor. In this case, the process consists of continuously charging the first reactor with a solution of SAN Ma) IJ lux in an inert solvent and also continuously charging the reactor with a separate portion of the diolefinic compound. , the latter being used in an amount that depends on its content in the SAM matrix of the solution and can vary between about 20 and about 40% of the total amount of diolefinic compounds. The remainder of this diolefinic compound is then continuously fed into a second reactor and/or
or continuously into a tube connecting the first and second reactors.

Diolefinic compounds, more particularly butadiene, mean that the final ABS resin contains from about 3 to about 20 wt.% butadiene, more preferably from about 4 to about 10 wt.% butadiene, with the remainder being a SAM copolymer. Used in such amounts that it is a combination.

ABS resin is continuously removed from the second reactor and treated to remove solvent and residual bodies. This treatment can be carried out using known means. According to an embodiment of the invention, the mixture removed from the second reactor is first subjected to a heat treatment in order to remove untreated diolefinic compounds as rapidly as possible and then, for example, in a dgvolatiliter or A second treatment is carried out on a Fi/L/A type evaporator to remove the solvent and remaining monomers. The ABS resin is then extruded, typically in the presence of antioxidants and optionally a universal plasticizer. By using the above method, it has been found that the final ABS resin is substantially free of abrasives, such as diolefinic compounds.

In the produced ABS resin, the in-situ produced rubber is very highly dispersed in the continuous SAM phase, and the final resin is virtually gel-free.

In previous methods of producing rubber-reinforced styrenic resins, styrene or a mixture of styrene and acrylonitrile was polymerized in the presence of rubber.

This latter is particularly effective when it is present during the polymerization of monomers (styrene or styrene and acrylonitrile). Grafting of certain monomers to the rubber occurs and the polystyrene or styrene-acrylonitrile copolymer region reaches a volumetric portion of the reinforcing rubber phase in which it is dispersed.

This rubber contains double bonds that provide grafting sites, and a high proportion of styrenic polymer chains are chemically grafted onto the rubbery electropolymer chains.

In contrast, when the method of the present invention is used, the copolymer
IJ Lux is first prepared and then a mono-ψ material is added to the matrix and then polymerized to produce a rubbery polymer. This latter is only partially grafted onto the matrix. However, the generated ABS'! It has been unexpectedly found that M fat contains enhanced properties.

Because the monomeric material is uniformly dispersed in the copolymer matrix and the concentration of this monomeric material is confined only to the matrix and does not produce separate rubbery polymer particles, thus there is no gel formation. , it is believed that the above results can be obtained.

The final ABS resin is characterized by a high degree of homogeneity of the rubber particles throughout the copolymer matrix.

The above aspects of the invention are set forth to illustrate some applications. Modifications may be made without departing from the scope of the invention. For example, the method can be modified by sequentially applying low amounts of butadiene (1) and styrene (S).
Particularly valuable results are obtained when applied to the polymerization of butadiene in the presence of a SAW matrix made from a mixture of styrene and acrylonitrile monomers containing block copolymers. B-8-
Known linear or radial block copolymers of type B or 5-B4 may be used in amounts generally not exceeding about 5%, based on the total weight of styrene and acrylonitrile monomers.

Patent Applicant: Labofuina Société Anonymous Continued from Page 1 @ Inventor: Emmanuel φ Lanser - 8 Avenue du Gobre d'Or, Brussels, Belgium

Claims (1)

[Claims] 1. α) Continuously feeding into a polymerization zone a mixture obtained by adding a diolefin compound to a solution of a copolymer matrix of a styrene compound and acrylonitrile in an inert solvent, and then subjecting the mixture to bulk polymerization conditions, thereby forming a rubber-like material in situ as a liquid dispersion in the copolymer matrix; b) continuously removing the reaction mixture from the polymerization zone;
and heat-treating it to remove residual diolefin compounds and solvents, and 6) recovering ABS resin. Continuous manufacturing method for mold resin. 2. The method according to claim 1, wherein the styrenic compound in the copolymer matrix is styrene. 3. The method of claim 1, wherein the violet of styrenic compound in the copolymer matrix is in the range between about 20 and about 90% by weight. 4. The method of claim 3, wherein the overlapping ratio of styrenic compound to acrylonitrile is in the range between about 4=1 and about 1:1. & Claim 1, wherein the copolymer matrix contains a sequential block copolymer of butadiene and styrene with a lid not exceeding 5% based on the total weight of the styrenic compound and acrylonitrile. Method described. & The method of claim 1, wherein the inert solvent has a boiling point in the range between about 1200-175U. 7. The method of claim 6, wherein the solvent has a boiling point in the range between about 1300 and 150c. & The method according to claim 1, wherein the solvent is an alkylbenzene. 9. The method according to claim 8, wherein the alkylbenzene is ethylbenzene. 10. The method of claim 1, wherein the solution of copolymer matrix contains from about lθ to about 70% by weight copolymer matrix. 2. The method of claim 1, wherein the 1t solution contains from about 20 to about 50 wt% copolymer matrix. 12 The diolefin compound is a conjugated diolefin hydrocarbon. A method according to claim 1. 13. The method of claim 12, wherein the li diolefinic hydrocarbon is butadiene. 14. The method of claim 1, wherein the diolefinic compound is used in an amount between about 3% and about 20% based on the weight of the final ABS-type resin. 15. The method of claim 14, wherein the amount of li diolefinic compound is within a range of between about 4% and about 10% based on the weight of the final ABS-type resin. 1a the polymerization zone has two reactors and a solution of the copolymer matrix and a fraction of the diolefinic compound are continuously introduced into the first reactor at a temperature within the range of about 60C to about 900C; 2. The method of claim 1, wherein the mixture is continuously removed from the first reactor and then added into a second reactor for polymerization of diolefinic compounds. 17. The polymerization zone has two reactors, and the copolymer polymer IJ lux solution and a portion of the diolefinic compound in a portion of the total amount are continuously added into the first reactor; The method of claim 1, wherein the resulting mixture is continuously removed from the first reactor and then added to the second reactor together with the remainder of the diolefinic compound. li The amount of diolefinic compound added into the first reactor is from about 20 to about 40% of the total number of diolefinic compounds.
18. The method of claim 17, wherein the %. 19. Bulk polymerization, copolymer polymer) 0.02 to about 25% based on the total weight of IJ lux and diolefinic compound
2. The process according to claim 1, wherein the process is carried out in the presence of a free radical generating catalyst used in a range between % and %. 20. The method of claim 19, wherein the amount of 2α catalyst is in the range of about O,OS to 15% based on the weight of the copolymer matrix and diolefinic compound.