KR19990060688A - Manufacturing method of acrylic impact modifier with improved weather resistance and impact resistance - Google Patents

Abstract

The present invention relates to a method for producing an acrylic impact modifier having improved weather resistance and impact resistance, and more specifically, a low Tg alkyl acrylate (-60 ° C. to −5 ° C.) polymer having a high Tg vinyl monomer (70 ° C. or more). ) To prepare a primary core of an inter-penetrating polymer network (IPN) or cellular structure by swelling or infiltrating and reacting with a low Tg monomer to prepare a secondary core, followed by hard-shell A method of making a core-shell polymer surrounded by a polymer. The core-shell polymer can solve the processing problem caused by improving the surface properties of the thermoplastic resin, improving the dimensional stability, expanding the processing area and increasing the size of the rubber phase to obtain the desired physical properties.

Description

Manufacturing method of acrylic impact modifier with improved weather resistance and impact resistance

The present invention relates to a method for producing an acrylic impact modifier with improved impact resistance and workability while maintaining weather resistance, and more specifically, polyvinyl chloride (hereinafter referred to as PVC), polystyrene (PS), and styrene-acryl, which are thermoplastic resins. The present invention relates to a method for preparing an acrylic impact modifier having a multi-layered core-shell structure used to improve weather resistance and impact resistance in a composition of ronitrile copolymer and poly methyl methacrylate (PMMA).

Generally, the impact modifiers widely used for the impact reinforcement of the polymer are acrylonitrile-butadiene-styrene (ABS), methyl methacrylate-butadiene-styrene (MBS), and acrylic rubber-styrene-acrylonitrile (ASA). , Halogenated polyethylene (CPE), ethylene vinyl acetate (EVA), and acryl-based, which have different processing areas depending on the resin composition, and are restricted by mechanical properties and environment used. Among the impact modifiers, the impact modifier using a rubber phase having an unsaturated double bond is difficult to be used in outdoor products due to the deterioration of physical properties due to color change and structural change by ultraviolet rays, and impact modifiers such as CPE and EVA. The weather resistance and impact reinforcing effect is excellent, but there is a disadvantage that the processing method and temperature range are largely limited in use because the variation is large depending on the processing area during processing to obtain the desired impact reinforcing effect. Unlike these, acrylic impact modifiers are widely used in various resins for outdoor use because they have no unsaturated double bonds and have excellent weather resistance and less variation in physical properties according to processing conditions.

Acrylic impact modifiers are manufactured by a continuous multi-stage emulsion polymerization method, and the structure is a hard rigid elastomeric rubber core particle having a low glass transition temperature (hereinafter referred to as Tg) with high Tg and excellent compatibility with a target matrix resin. It has a core-shell structure surrounded by a shell polymer. A method of manufacturing an acrylic impact modifier having a core-shell structure is described in detail in US Pat. Nos. 3,655,825 and 4,180,529, Japanese Patent Publication No. 73-44956, and the like. Alkyl acrylates having at least% by weight alkyl groups of 2 to 8 carbon atoms, in particular alkyls having up to 50% by weight of alkyl groups having 1 to 4 carbon atoms in the presence of an elastomer core containing butyl acrylate and a small amount of crosslinking agent, graft agent It is known to produce impact modifiers having a core-shell structure by grafting methacrylate monomers, in particular methyl methacrylate.

It is known that the rubbery particles forming the core have a uniform and constant size, and most of the mechanical properties of the workpiece are controlled by the particle size with specific gravity at impact strength, so that the particle size of the elastic rubbery core is 0.15㎛ to 0.25㎛. It is known that the degree of impact strength and workability is excellent, and the elastic rubber-like cores possessed by the above patents change elastic properties by the type and amount of crosslinking agent, and also affect the overall mechanical properties according to the type and amount of graft agent. Receive. In consideration of these effects, methods of polymerizing the crosslinking agent and the graft agent artificially using a continuous controlled polymerization method have been proposed. In general, in order to uniformize and adjust the size of rubbery particles, a polymerization method is performed through a seeding step due to the simplification of the process and the ease of particle size adjustment, which is described in detail in Korean Patent Publication No. 87-292. It is explained.

The patent is designed to have an impact reinforcing effect by having a seeding composition similar to that of an elastic rubber-like core or having the same composition, and by controlling their particle size, it is shown that the physical properties of the desired final product are obtained. .

The patents have almost the same properties as the composition of the rubbery core, and the disadvantage thereof results in deterioration of surface properties and overall physical properties due to deformation of the rubbery core when using a processing method subjected to high shear stress.

The above products have the disadvantage of deteriorating the appearance of the processed molded article and deteriorating mechanical properties when using the processing method in which the rubber particle size is increased and high shear stress is generated to obtain the desired physical properties. Increasing the degree of crosslinking of the rubbery phase to withstand high shear stresses results in the loss of the impact energy absorption, thus losing the purpose of the original impact modifier.

The present inventors have conducted extensive research to solve the above-mentioned problems, and have found a method that can solve the above-mentioned problems, and the invention has been completed based on this.

An object of the present invention is a high shear in a method that can compensate for and improve the above-mentioned problems, in particular, the disadvantages such as deterioration of physical properties due to deformation of the rubber phase under high shear stress and reduction of dimensional stability due to shrinkage of the elastic rubber phase generated after processing. It is to provide a method of manufacturing a core-shell impact modifier having a multilayer structure that can express the inherent properties of the impact modifier by minimizing the deformation of the rubber phase under stress.

The production method of the present invention for achieving the object of the present invention comprises the steps of: 1) preparing a seed by polymerizing a low Tg of 10 to 40% by weight, strong hydrophilic alkyl acrylate, a small amount of a crosslinking agent and a graft agent; 2) preparing a primary core with an morphology of IPN or a cellular structure by polymerizing a hydrophobic strong vinyl monomer having a high Tg of 5 to 30% by weight to the seed prepared in step 1); 3) preparing a secondary core by polymerizing 30 to 60% by weight of the low Tg rubbery monomer in the primary core prepared in step 2); 4) preparing a hard-shell by polymerizing a mixture of 5-20 wt% high Tg alkyl methacrylate or aromatic vinyl compound and low Tg alkyl acrylate to the secondary core prepared in step 3). ; And 5) drying the core-shell polymer of step 4) to prepare a powder having an average particle diameter of 150 μm.

Looking at the present invention in more detail as follows.

The present invention will be described step by step as follows.

A) in the first step, emulsion-polymerizing a seed composed of a low Tg alkyl acrylate (-60 deg. C to -5 deg. C) and a small amount of a crosslinking agent and a graft agent by a continuous addition method;

B) In the second step, in the presence of the seed prepared in the first step, the vinyl monomer having a high Tg (70 ° C. or more) is subjected to emulsion polymerization in a semi-batch, continuous or intermittent manner. Prepare primary core polymers in the form of Interpenetrating polymer networks (IPNs) or cellular structures.

C) In the third step, after forming a secondary core including a low Tg alkyl acrylate monomer and a certain amount of a crosslinking agent and a graft agent in the presence of the second step polymer,

D) In a fourth step, the final emulsion polymer is obtained by grafting a hard-shell having a high Tg in the presence of the polymer of the third step.

In general, when the material constituting the sheath is replaced with a vinyl monomer having a high Tg to have a multilayer structure, deformation of the elastic rubber phase can be prevented to some extent under high shear stress, but overall mechanical properties and impact reinforcing effects are obtained. In order to limit the amount of high Tg monomer used, there is a disadvantage that the impact reinforcing effect is somewhat lower than the above patents. In addition, in order to solve the problems listed above, when the copolymer is produced by changing the composition of the monomer having a low Tg and the monomer having a high Tg, the modulus of the rubber phase is increased, thereby reducing the impact reinforcing effect, particularly at low temperatures. There is a problem that the impact reinforcing effect is lower than the conventional weathering impact modifier.

A feature of the present invention is that the morphology of the morphology (i. It is characterized by having a celluar) structure, not only to have the same characteristics as a general core-shell impact modifier, but also to extend the processing area of a weather resistant impact modifier having a limited processing range.

The child characterized here. Structures and cellular structures exhibit different properties from common core-shell structures or copolymers. In general, the core forming part of the core-shell is a copolymer of a single polymer or a copolymer of two or more monomers, mostly by a single monomer, and these are physical properties that do not retain the characteristics of each monomer, but have mutual advantages. By taking the or taking away the drawbacks, you bring up a whole new characteristic. Unlike the copolymers, the I.P.ene structure or the cellular structure keeps the monomers to be copolymerized with their respective properties. In many cases, they are manufactured by physical and chemical methods and have a kind of polymer blend characteristics.

In general, a method for producing an I.P.ene structure or a cellular structure is obtained by making one polymer into a network structure, infiltrating another monomer with it, swelling the monomer in the polymer of the network structure, and then performing polymerization. Can be.

In the case of using a polymerization method using a common core-shell morphology, the amount of the monomer having a high Tg that can be used in the seed step is somewhat limited in order to obtain the desired physical properties, and as in the comparative example of the present invention, 10 wt% It was difficult to overcome the above problems, and the impact reinforcing effect and other physical properties were found to be lower than those of the I.P. structure or the cellular structure.

However, when preparing a seed having an I.P.en or cellular structure as in the present invention, the amount of the monomer having a high Tg is possible up to 5 to 30% by weight of the total polymer, and as the amount thereof increases, the modulus is increased. It also increases the thermal deformation temperature and dimensional stability of the final molding, and the impact energy absorption effect can be the same as the general impact modifier, and high shear stress even if the rubber phase is adjusted to obtain the desired properties. It has the advantage of minimizing the deformation of the rubber phase. Preferably, the amount of the monomer having a high Tg that can maximize the impact reinforcement effect and minimize the deformation of the rubber phase is appropriately 10 to 20% by weight of the total polymer. When the amount of the monomer having a high Tg is 5% by weight or less of the entire polymer, there is a problem in that the rubber phase is deformed under high shear stress, whereas when it exceeds 30% by weight, the impact reinforcing effect is lowered.

Monomers used in the seed of step a) are alkyl acrylates having 1 to 8 carbon atoms, such as methyl acrylate, ethyl acrylate, isopropyl acrylate, butyl acrylate and 2-ethyl hexyl acryl. One or more selected from the group consisting of a latex and octyl acrylate, the amount of which is suitably 10 to 40% by weight of the total polymer, and if the amount of the monomer used in the seed is less than 10% by weight, There is a problem in forming an I.P. structure with a monomer having a high Tg, and when it exceeds 40% by weight, there is a problem in that rubber modulus is difficult to adjust.

In addition, the crosslinking agent used in step a) may be aryl methacrylate, dimethacrylate, for example ethylene glycol dimethacrylate, 1,3-butanediol dimethacrylate, 1,4-butanediol dimethacrylate, 1 It is selected from the group consisting of, 6-hexanediol dimethacrylate, the amount of the crosslinking agent is appropriately 0.05 to 3% by weight, preferably 0.07 to 2% by weight relative to the monomer component forming the seed. In addition, the graft agent of step a) is selected from the group consisting of aryl methacrylate, ethylene glycol dimethacrylate, triaryl cyanurate, glycidyl methacrylate, and the amount of the graft agent is based on the seed monomer. 0.02 to 2% by weight, preferably 0.08 to 1.5% by weight is suitable. As polymerization initiators, water-soluble radical initiators are used, examples of which are used alone or in combination with a group of thermal dissociation initiators consisting of ammonium persulfate, sodium persulfate, and potassium persulfate and alkali metal sulfite, hyposulfite and sodium. Oxidation-reduction initiators in the form of a mixture with a reducing agent such as formaldehyde sulfoxylate are used, and the amount thereof is suitably used in an amount of 0.02 to 2.0 wt% based on the seed monomer.

The monomer used in step b) is one or more selected from the group consisting of vinyl monomers having a high Tg, especially alkyl methacrylate, styrene, α-methyl styrene, p-methyl styrene, and acrylonitrile. The stronger this is, the more suitable the amount used is 5 to 30% by weight of the total monomer used in the impact modifier. When less than 5% by weight, the rubbery deformation occurs under high shear stress, and when more than 30% by weight, the impact reinforcing effect is lowered. Preferably 10 to 20% by weight is used.

The crosslinking agent and graft agent used in step b) are those exemplified in the above seed, and the amount of the crosslinking agent and the graft agent is 0.01 to 1% by weight based on the monomers, and the initiator used is an oil-soluble radical initiator such as dicumyl hydro Peroxide, benzoyl peroxide, lauroyl peroxide, azobis butyrylonitrile, and the like, and the reducing agent used at this time includes ethylene diamine tetra sodium acetate, anhydrous glucose, tetra sodium pyrophosphate, Sodium ferro sulfate. It is selected from the group consisting of sodium hydrogen sulfite, sodium aldehyde sulfoxylate and the like is appropriate amount of 0.02 to 0.8% by weight based on the monomer.

The secondary core composition of step 3) uses monomers exemplified on the elastic rubber of the sheath, and its amount is suitably 30 to 60% by weight based on the total composition of the impact modifier, and when the amount is less than 30% by weight, the modulus of rubber is increased. When the impact reinforcing effect is lowered and exceeds 60% by weight, the elastic modulus decreases, resulting in deformation of the rubber phase under high shear stress. The crosslinking agent and graft agent of step c) are also used in the above examples, and the amount thereof is used in an amount of 0.05 to 2% by weight based on the monomer. These are emulsion-polymerized by a continuous addition method in a pre-emulsion state to obtain an elastomeric rubbery core composition. At this time, the particle size of the elastic rubber phase is appropriately 0.15㎛ 0.30㎛.

As monomers used in the shell-forming hard polymer of step d), alkyl methacrylate having a high Tg, aromatic vinyl compound may be used alone, or mixed with an alkyl acrylate monomer having a low Tg. One or more selected from the group consisting of latex, styrene, α-methyl styrene, p-methyl styrene, and one or more selected from the group consisting of methyl acrylate, ethyl acrylate and butyl acrylate. The amount of these used is 5 to 20% by weight based on the total impact modifier monomer, and the water-soluble radical initiator described above is used as the radical polymerization initiator. The amount used is from 0.1 to 1.5% by weight based on the monomer.

As the emulsifier used in the present invention, anionic or nonionic emulsifiers are used alone or in combination, and the amount of the emulsifier is 0.2 to 2.5% by weight based on the total monomers. Exemplary anionic emulsifiers are selected from the group consisting of sodium lauryl sulfate, sodium dodecyl sulfate, sodium dodecyl benzene sulfate, potassium dodecyl sulfate, sodium dodecyl benzene sulfonate and dioctyl sodium sulfur succinate, and nonionic emulsifiers As an example, octyl phenoxy polyethoxy ethanol, nonyl phenoxy poly epoxy ethanol, etc. are mentioned.

The core-shell polymer prepared by the above method is used as a powder-based resin having an average particle diameter of 120 to 150 μm through a spray dryer, and the acrylic multilayer structure impact modifier prepared as described above has a rubbery deformation even under high shear stress. Minimizes, contributes to the thermal stability and dimensional stability of the final product, and has the advantage of improving the surface properties, such as polyvinyl chloride, polystyrene, poly methyl methacrylate, polycarbonate, polyethylene terephthalate, poly butylene terephthalate, etc. It is mixed with resin to express impact reinforcing effect and weather resistance.

The core-shell polymer also consists of 20 to 40 weight percent primary core polymer, 30 to 60 weight percent secondary core polymer, and 10 to 20 weight percent hard-shell polymer.

Hereinafter, the present invention will be described in more detail with reference to Examples, but the scope of the present invention is not limited in the following Examples.

Example 1

40 weight% of ion-exchanged water was added to a 5-liter four-necked flask equipped with a thermometer, a dropping tank, a cooler, and a stirrer, and the temperature was raised to 80 ° C., 15 weight% of ion-exchanged water, and 0.08 weight% of sodium dodecyl benzene sulfonate. The total emulsion, consisting of 0.06% by weight of potassium persulfate, 29.8% by weight of butyl acrylate and 0.2% by weight of aryl methacrylate, was continuously added to a four-necked flask to obtain a first stage polymerization reaction. The particle diameter of the polymer obtained at this time is 0.12 micrometer.

After adjusting the temperature of the first stage polymerization reaction to 60 ° C. by the second stage polymerization, 5% by weight of ion-exchanged water, 0.01% by weight of ethylene diamine tetra sodium acetate, 0.04% by weight of sodium dodecyl sulfoxylate, ferric sulfate Add 0.001% by weight and again add 9.95% by weight of styrene, 0.05% by weight of arylmethacrylate and 0.2% by weight of dicumyl hydroperoxide to complete the polymerization. The particle size of the polymer obtained at this time is 0.14 탆.

After completion of the second stage polymerization by the third stage reaction, the temperature was raised to 80 ° C, and 35 wt% of ion-exchanged water, 0.25 wt% of sodium dodecyl benzene sulfate, 0.05 wt% of potassium persulfate, and 39.78 wt% of butyl acrylate The total emulsion consisting of 0.2% by weight of aryl methacrylate and 0.02% by weight of 1,6-hexanediol dimethacrylate was added dropwise to a 5 L four-necked flask to complete the secondary core reaction. The particle diameter of the polymer obtained at this time was 0.23 micrometer.

The fourth stage reaction was carried out after the third stage reaction consisting of 5% by weight of ion-exchanged water, 15% by weight of methyl methacrylate, 5% by weight of ethyl acrylate, 0.2% by weight of sodium dodecyl benzene sulfate, and 0.05% by weight of potassium persulfate. The emulsion was added dropwise by the continuous addition method to effect polymerization. The particle diameter of the finally obtained polymer is 0.27 micrometer.

The emulsion latex obtained after the completion of the polymerization reaction was obtained by a spray dryer to obtain a powder impact modifier having an average particle size of 150 ㎛ 100% by weight, 8% by weight of the impact modifier obtained above, stabilizer 3% by weight, lubricant 1.5 wt% and 5 wt% of the inorganic filler were mixed and extruded to obtain a sheet. The results of the measurement of the physical properties are shown in Table 1. Table 2 shows the results measured by injection after mixing as shown in Table 2 to the PVC having a lower polymerization degree than the PVC used in the above formulation.

Example 2

In Example 1, the amount of the first stage polymerization monomer was 20% by weight, the amount of the crosslinking agent was adjusted according to the monomer change, and the amount of the monomer was increased to 20% by weight during the second stage polymerization, and the crosslinking agent and the graft agent were added to the monomer change. Adjusted accordingly. In addition, in order to make the particle size of the polymer obtained at this time the same as Example 1, the amount of emulsifier was adjusted and the polymer of 0.15 micrometer was obtained.

The polymerization of the third and fourth stages was performed in the same manner as in Example 1, and the particle size of the third rubber phase was adjusted to 0.21 μm. Physical property measurement results are shown in Table 1 and Table 2.

Example 3

The same polymerization method as in Example 1 was used, and the amount of the first stage polymerization monomer was 10% by weight, and the amount of the crosslinking agent was adjusted according to the monomer change.In the second stage of polymerization, the amount of monomer was increased to 30% by weight, and the crosslinking agent, The graft agent was adjusted according to the monomer change. In order to control the particle diameter of the polymer, the amount of emulsifier was changed to obtain a polymer of 0.14 mu m.

The polymerization of the third and fourth stages was performed in the same manner as in Example 1, and the particle size of the third rubber phase was adjusted to 0.22 μm. Physical property measurement results are shown in Table 1 and Table 2.

Example 4

The polymerization was carried out using the same method as in Example 3, and the polymerization was completed by adjusting the particle size to 0.25 μm and adjusting the third rubber phase particle size to 0.4 μm during the second stage of polymerization. Physical property measurement results are shown in Table 1 and Table 2.

Comparative Example 1

The polymerization was carried out in the first step and the second step polymerization in Example 1 in the form of a core-shell, not a semi I. P. structure, and 9.95% by weight of styrene and 0.05% by weight of aryl methacrylate were used in the first step. The polymerization was carried out using an oxidation-reduction reaction. In the second stage polymerization, 69.6 wt% butyl acrylate, 0.32 wt% aryl methacrylate, and 0.08 wt% potassium persulfate in 0.08 wt% of 1,6-hexanediol dimethacrylate , 0.34% by weight of sodium dodecyl benzene sulfate was added dropwise to the polymerization tank by the continuous addition method to advance the polymerization, and the amount of the emulsifier was adjusted to give a rubbery particle diameter of 0.21 μm. The final shell step was carried out in the same manner as in Example 1. Physical property measurement results are shown in Table 1 and Table 2.

Comparative Example 2

Polymerization was carried out in the same manner as in Comparative Example 1 except that the styrene content was increased to 15% by weight in Comparative Example 1, and the amount of the emulsifier was adjusted to obtain a polymer having a rubbery particle diameter of 0.23 μm. The results are shown in Table 1 and Table 2.

Comparative Example 3

The polymerization was carried out in the same manner as in Comparative Example 1 except that the styrene content was increased to 20% by weight in Comparative Example 1, and a polymer having a rubbery particle diameter of 0.23 μm was obtained by controlling the amount of the emulsifier. The results are shown in Table 1 and Table 2.

Comparative Example 4

The first stage polymerization was seed polymerization using 4.8% by weight of butyl acrylate, 0.03% by weight of crosslinking agent, 0.15% by weight of graft agent, and 0.03% by weight of potassium persulfate, which is a water-soluble initiator. The monomer used in the three-step core polymerization was prepared by emulsifier, ion-exchanged water, initiator and preemulsion with 74.8% by weight of butyl acrylate, 0.1% by weight of crosslinking agent, and 0.3% by weight of graft agent. The amount of the emulsifier was adjusted to obtain a polymer having a rubbery particle diameter of 0.22 탆. The final shell stage polymerization proceeded in the same manner as in Example 1. The results of the physical properties are shown in Table 1 and Table 2.

Comparative Example 5

In the first stage polymerization, a low Tg acrylate, in particular butyl acrylate, and a high Tg styrene monomer were copolymerized to prepare a seed, followed by core polymerization and shell polymerization. The ratio of the copolymer of the seed step was used as the composition ratio of the first step and the second step shown in Example 1, the polymerization method is ion butyl acrylate, styrene, emulsifier initiator as in the first step polymerization of Example 1 The polymerization was carried out by pre-emulsification in exchanged water and dropwise addition by a continuous addition method, and potassium persulfate, which is a water-soluble initiator, was used as an initiator. The polymerization of the core was carried out in the same manner as in Example 1, and the amount of the emulsifier was adjusted to control the core. A particle diameter of 0.2 占 퐉 was produced. Shell polymerization was carried out by the same amount and method as in Example 1. Physical property results are shown in Table 1 and Table 2.

Extrusion Processability and Property Comparison Rubber Particle Size (㎛) Extrusion rate g / min Extrusion Torque m.g Charpy Impact Strengthkg.cm/cm Heat deformation * △ E ** Example 1 0.23 70.5 9760 37.2 0.12 1.7 Example 2 0.21 69,8 9730 36.8 0.15 1.7 Example 3 0.22 68.7 9724 37.1 0.17 1.9 Example 4 0.40 72.8 9638 34.2 0.19 1.8 Comparative Example 1 0.21 66.4 9835 30.2 0.21 2.2 Comparative Example 2 0.23 66.7 9821 29.8 0.23 2.4 Comparative Example 3 0.23 65.7 9784 27.5 0.27 2.7 Comparative Example 4 0.22 65.4 9820 25.6 0.34 1.7 Comparative Example 5 0.20 68.8 9747 32.6 0.28 1.8

-Extrusion condition: twin screw extruder, extrusion temperature (℃) C1 / C2 / C3 / D = 180/185/190/190,

Screw rpm: 30, Extrusion mold: 10 × 2.5t sheet die

* Heat deformation: Extruded sheet is cut to proper length, and the front and back distances are marked and aged for 1 hour at 100 ℃, and left at room temperature for 24 hours to calculate shrinkage.

** △ E: Weathering tester (Xenon arc, 500 hours)

Injection property comparison Izod impact strength (kg.cm/cm) Tensile Strength (kg / ㎠) Tensile Elongation (%) Surface Gloss (60 ') 1/4 1/6 Example 1 16.8 39.4 412 105 74 Example 2 15.4 38.5 417 98 71 Example 3 15.0 38.2 421 97 72 Example 4 22.2 45.7 401 118 71 Comparative Example 1 7.2 30.5 394 93 70 Comparative Example 2 7.0 29.8 376 100 68 Comparative Example 3 5.8 22.5 381 88 66 Comparative Example 4 2.6 22.6 320 75 58

Compound Compounds Used

PVC (polymerization degree; 700): 100 * Izod impact strength: ASTM 256

Impact modifier 10 * Tensile strength and elongation: ASTM 638

Stabilizer 4.0

Bow 3.8

Filler 5.0

The core-shell impact modifier prepared by the manufacturing method of the present invention can compensate for and improve the disadvantages such as deterioration of physical properties due to deformation of rubber phase under high shear stress and dimensional stability due to shrinkage of elastic rubber phase generated after processing. It minimizes deformation of rubber phase even under high shear stress and improves impact reinforcement effect, weather resistance and impact resistance by mixing with hard thermoplastic resin.

Claims (5)

In the method for producing an acrylic impact modifier for thermoplastic resin consisting of a seed / core / shell, 1) preparing a seed by polymerizing a low Tg and strong hydrophilic alkyl acrylate, a small amount of crosslinking agent and a graft agent of 10 to 40% by weight; 2) preparing a primary core with an morphology of IPN or a cellular structure by polymerizing a hydrophobic strong vinyl monomer having a high Tg of 5 to 30% by weight to the seed prepared in step 1); 3) preparing a secondary core by polymerizing 30 to 60% by weight of the low Tg rubbery monomer in the primary core prepared in step 2); 4) preparing a hard-shell by polymerizing a mixture of 5-20 wt% high Tg alkyl methacrylate or aromatic vinyl compound and low Tg alkyl acrylate to the secondary core prepared in step 3). ; And 5) A method of manufacturing an acrylic impact modifier having improved weather resistance and impact resistance, comprising the step of drying the core-shell polymer of step 4) into a powder having an average particle diameter of 120 to 150 μm. The method of claim 1, wherein the monomer having a high Tg of step 2) is selected from the group consisting of methyl methacrylate, styrene, α-methyl styrene, p-methyl styrene and acrylonitrile. Manufacturing method. The method according to claim 1, wherein the low Tg and hydrophilic monomers of steps 1) and 3) are methyl acrylate, ethyl acrylate, isopropyl acrylate, butyl acrylate, 2-ethyl hexyl acrylate and octyl acrylate. One or more manufacturing method selected from the group consisting of. The method of claim 1, wherein in the step 2), the reactants are placed in a batch, continuous, or intermittent dropwise manner to change the morphology of the primary core. The method of claim 1, wherein the core-shell polymer is characterized in that consisting of 20 to 40% by weight of the primary core polymer, 30 to 60% by weight of the secondary core polymer, 10 to 20% by weight of the hard-shell polymer Manufacturing method.