KR890003260B1 - Vinyl halide polymer composition with improved weather resistance and workability - Google Patents

Abstract

Vinyl halide polymer composition having weather-resistance and workability comprises of hydrated alumina of 0.4-0.6 micron av. particle size and impact-modifier filler.

Description

How to increase impact resistance of halogenated vinyl polymer composition and halogenated vinyl polymer

1 is a graph showing the relationship between Izod impact strength and hydrated alumina concentration.

2 is a graph showing the relationship between the hydrated alumina concentration, the extrusion pressure and the amperage of the motor.

3 is a graph showing the effect on the weathering resistance of hydrated alumina and calcium carbonate.

FIELD OF THE INVENTION The present invention relates to halogenated vinyl polymer compositions, and in particular to the use of hydrated alumina of ultrafine particle size (average of about 1 μm or less), which forms an impact modifier and synergistic composition in a halogenated vinyl polymer composition, preferably a hard composition. .

In general, the most commonly sold vinyl halidepolymer material is polyvinyl chloride (PVC), which will be described later with respect to PVC in the present invention. However, it can be seen that it can be used for other vinyl halide polymers as described below.

When used at low concentrations to reduce cost, fillers are added to the halogenated vinylpolymer material to perform a scrybbing action or reduce plateout. Typically, increasing their concentration to have sufficient effect on physical properties, fillers increase modulus, reduce tensile strength and elongation, and typically reduce impact strength. Some fillers that reinforce and maintain impact strength in rigid PVC compositions include particulate precipitation, hydrated silica and ultrafine coated precipitated calcium carbonate [J. Radosta, 37th SPE Annual Technical Conference Preprints, Pg. 593 (1979)]. These fillers are not widely used for external rigid PVC because they have a detrimental effect on weathering resistance.

Hydrated alumina is used as an additive for plastic parts, and its value is low, as its flame resistance and flame retardancy are widely introduced in the literature (J.Z. Keating, Plastics Compounding, Pg. 23, July / august, 1980). Most of the applications of hydrated alumina in the PVC compounds described in the literature are limited to plasticizing compositions which can achieve improved flame retardancy when used at concentrations of about 10 parts or more per polymer part [AWMorgan, TCMathis and JD]. Hirchen, 30th SPE Annual Technical Conference Preprints, Chicago, Pg. 475 (1972): "R.W. Sprague, Systematic Study of Firebrake ZB on Flame Retardants in PVC-Part 4, Trihydrate Alumina as Synergist", April, 1973, January, 1975, U.S. Borax Research Corporation, Anaheim, California; C.E.Hoke, SPE Journal, 29 Pg. 36 (May, 1973)], however, I. Sobolev and EAWoychesin, SPE Annual Technical Conference Preprints, Pg. 709 (1973), described the use of 40% concentration of hydrated alumina in hard PVC as a flame retardant. It can be seen that the impact strength is not reduced. Furthermore, for example, US Pat. No. 3,957,723 to Lotion et al., US Pat. No. 3,985,706 to Kay, US Pat. Or improved flame retardancy and flame retardancy by synergism of bismuth bicarbonate.

In the present invention, the ultra-fine particle size (less than 1μ) of hydrated alumina is not only used as an additive for PVC that does not reduce the impact strength of PVC, but also unexpectedly shows a high synergistic effect with a conventional impact modifier to significantly increase the impact strength. It can be seen that by improving the workability and weathering resistance.

Hydrated alumina is commonly called hydrated alumina or trihydrate alumina. The empirical formula is represented by Al ₂ O ₃ · 3H ₂ O because it shows flame retardancy by decomposition into aluminum oxide and water at elevated temperatures. However, this equation is technically incorrect. This compound is actually finely ground crystalline aluminum hydroxide represented by the formula Al (OH) ³ .

Hydrated alumina of ultrafine particle size (average about 1 micron) is useful as a filler in halogenated vinyl polymers and, when used in combination with impact modifiers, synergistically increases the impact strength of PVC materials. The present invention provides a method for increasing the impact resistance of a halogenated vinyl polymer material, the amount of impact modifier forming an elevated combination to increase the impact resistance of the halogenated vinyl polymer material and an average particle of about 1 μm or less. By means of mixing the sized hydrated alumina into the halogenated vinylpolymer material. Also in accordance with the present invention. A halogenated vinylpolymer composition having improved weathering resistance and processability is provided, which comprises a vinyl chloride polymer or copolymer, a hydrated alumina and a filler having an average particle size of less than 1 micron, and preferably the composition is combined with the hydrated alumina. Together with an impact modifier sufficient to form a synergistic composition that substantially increases the impact resistance of the polymer.

The present invention also provides a method for improving the weathering resistance of a halogenated vinyl polymer material mixed with a filler by mixing a hydrated alumina having an average particle size of about 1 μ or less with a halogenated vinyl polymer material containing a reinforcing filler. .

The present invention also provides a composition suitable for improving the impact resistance of a halogenated vinyl polymer material in which the hydrated alumina having an average particle of 1 μm or less and the impact modifier have a relative ratio sufficient to innovate the synergistic combination.

A hydrated alumina having an ultrafine particle size (average of 1 μm or less) is mixed with the impact resistant hard PVC composition to surprisingly obtain a PVC composition with a remarkably increased impact strength.

This effect is evidenced by the various impact resistance modifiers commonly used in rigid PVC applications.

The torque flow system and the extrusion test in the hard PVC composition containing the ultrafine particle size hydrated alumina, it can be seen that the motor ampere number and torque is reduced when the hydrated alumina concentration is increased.

Thus, an increase in dynamic stability can be observed.

Another advantage of the use of very fine particle sized hydrated alumina in exterior PVC compositions is improved weathering resistance, which can reduce the amount of titanium dioxide or other fillers commonly used in special applications. The composition in which the ultrafine hydrated alumina according to the present invention is combined at various concentrations shows excellent performance when the composition containing only titanium dioxide is subjected to an external exposure test and a weathering test. In addition, the composition containing titanium dioxide at a lower concentration than the hydrated alumina exhibits the same weathering resistance as the composition containing only high concentration of titanium dioxide.

As mentioned above, the term ultrafine particle sized hydrated alumina means hydrated alumina having an average particle size of about 1 micron or less, preferably about 0.5 micron (0.4-0.6 micron) or less. In general, if the average particle size of the hydrated alumina is larger than the above limit, it adversely affects the Izod impact strength of the polymer material.

The particle distribution of the hydrated alumina is preferably such that no particles having a particle size of about 1 mu or more are actually present.

"Impact strength" means Izod impact strength measured by the method of ASTN D-256. In general, this test produces a sample size of 2-1 / 2 × 1/2 × 1/8 or 1/4 inch, graduated to the test specimen as specified in the test method, and the cantilever beam. In the impact test, impact is applied to a test piece supported by an electric hammer.

The energy absorbed in the width of the sample is transferred to the recorded distance scale, in pounds, from which the impact strength, expressed in feet per inch of notch, is calculated. By "halogenated vinyl polymer" is meant homopolymers and copolymers derived from vinyl halides and polymer mixtures containing such homopolymers or copolymers as components. Homopolymers, copolymers and polymer mixtures containing vinyl halides useful in the practice of the present invention include, for example, (1) polyvinyl chloride, polyvinylidene chloride, polyvinyl chloride, polyvinyl fluoride and polyvinylidene fluoride; (2) vinylidene chloride, vinyl acetate, vinyl butyrate, vinyl benzoate, diethyl fumarate, diethyl maleate, other alkyl fumaric acid and maleic acid, vinyl propionate, acrylic acid, methyl acrylate, 2-ethylhexyl acrylate, butyl acrylate, Ethyl acrylate and other alkyl acrylates, methacrylic acid, methyl methacrylate, ethyl methacrylate, butyl methacrylate, hydroxyethyl methacrylate and other alkyl methacrylates, methyl alpha chloroacrylate, styrene, vinyl ethyl ether, vinyl chloroethyl ether Vinyl ethers such as vinyl phenyl ether, vinyl ketones such as vinyl methyl ketone and vinyl phenyl ketone, 1-fluoro, -1-choloethylene, acrylonitrile, chloroacrylonitrile, allylidene diacetate, chloroallyli Dendiacetic, one or more balls such as olefins such as ethylene and propylene Copolymers of polymerizable ethylenically unsaturated monomers with vinyl chloride (3) Polyvinyl chloride and polyethylene Polyvinyl chloride and polymethyl methacrylate, polyvinyl chloride and polybutyl chloride, polyvinyl chloride and polybutyl chloride and acrylonitrile Polymer mixtures such as mixtures of butadiene-styrene terpolymers and ternary mixtures containing polyvinyl chloride, polyethylene methacrylate.

Representative vinyl halide copolymers that can be used in the present invention include vinyl chloride-vinyl acetate, vinyl chloride-vinylidene chloride, vinyl chloride-diethylfumarate, vinyl chloride-trichloroethylene and vinyl chloride-2-ethylhexyl acrylate There is. Polymer blends that can be used in the practice of the present invention refer to physical mixtures of at least two or more completely different types of polymers, and generally contain 25-95 weight percent halogenated vinyl homopolymer or copolymer. Examples of vinyl halide copolymers that can be used in the present invention generally contain about 25-95 mole percent vinyl halide units.

A preferred feature of the composition is that the polymer is a homopolymer or copolymer of vinyl chloride. This is because vinyl chloride has higher commercial availability and lower cost than other vinyl halides. The ultrafine particle sized hydrated alumina described herein can be used as a filler in hard and soft vinyl halide polymer compositions and is obtained from hard halogenated vinyl polymer compositions (having less than 10% plasticizer) and has surprisingly good impact strength. In particular, commercial value is important.

When using ultra-fine particle size hydrated alumina according to the present invention

A. Synergistic Effects on Impact Resistance

When calcium carbonate filler having an average particle size of 1.0 mu or more is used in the rigid PVC composition, it has an adverse effect on the impact strength. If the average particle size is 1.0 μm or less, there is no loss in impact strength, and a slight improvement in impact strength occurs. In a composition containing an impact modifier and a calcium carbonate filler, the impact resistance is only slightly improved compared to that obtained by the impact modifier itself.

The ultrafine particle sized hydrated alumina used in accordance with the present invention only slightly increases the impact strength in hard compositions that do not contain an impact modifier. However, in a PVC composition containing an impact modifier, it differs from calcium carbonate. It exhibits a completely different action and synergizes with the impact resistance modifier to increase the impact strength to the expected circuit. The results are shown in Table 1.

The surprising unexpected increase in impact strength is independent of the type of impact modifier used in the composition. Generally, impact modifiers are rubbery materials, which are partially or completely incompatible with halogenated vinylpolymers and exist as discrete discontinuous phases. This is in contrast to plasticizers that are completely compatible with halogenated vinyl polymers. Moreover, impact modifiers increase impact strength without significantly reducing the heat deflection temperature or compromising other desired mechanical and physical properties. Representative impact modifiers suitable for use in the present invention are, for example, chlorinated polyethylene based, modified acrylic or unmodified acyl based, ABS and MBS modifiers.

Usually, the impact modifier can be used in the composition, and the ultrafine particle sized hydrated alumina continues to have a synergistic effect. For example, when 6 Phr of ultrafine particle size hydrated alumina is added to a hard PVC composition containing 5 Phr of a conventional impact modifier, the Izod impact strength is increased by 2 to 10 times or more compared to the case where no hydrated alumina is added.

The data in Table 2 is 5-20 ft.-1bs./in. Notch increases Izod impact

B. Hydrated Alumina Particle Size

The use of ultrafine particle size (average less than 1μ) hydrated alumina does not adversely affect the impact strength of the PVC composition, and the use of larger particle size hydrated alumina reduces the impact strength of the PVC composition, but The actual increase in impact strength achievable by using an impact modifier and a synergist of hydrated alumina of ultra-fine particle size (less than 1) is unexpectedly surprising.

Table 3 shows the synergistic effect on impact strength with hydrated alumina having an average particle size of about 1 μm or less. Having an average particle size of 1 μ does not affect the impact strength, while larger particle size materials adversely affect the impact strength.

C. Hydrated Alumina Concentration

In the present invention, the maximum impact strength is obtained when the ratio of the ultrafine particle size hydrated alumina or the impact modifier is 2-4: 1, and the impact strength is remarkably increased even when the ratio is 1: 1, and the ratio is greater than 1: 2. Useful effects can be achieved at low rates.

Some effects can be obtained at lower ratios, and in general, the ratio needs to be at least 1: 2 in order to obtain commercially good results.

For example, for a composition containing 3 Phr of modified acryl-based impact modifier, the maximum impact resistance is obtained when the ratio of the hydrated aluminum and the impact modifier is 2: 1. When the concentration of the hydrated alumina is increased until the ratio of the hydrated alumina and the impact modifier is 8: 1, an impact strength of 3 Phr is used and the same impact strength as in the case of not using the hydrated alumina is obtained. Reference).

Typically impact modifiers are used in the range of about 1-15 Phr, preferably about 2-10 Phr. Specific amounts vary with polymer material end use. For example, injection molding PVC typically has an impact modifier of about 2-3 Phr, while hard PVC for building walls has about 4-8 Phr of the modifier.

By using the ultrafine particle sized hydrated alumina according to the present invention, the concentration of the impact modifier is slightly reduced. Since the high impact modifier lowers the tensile strength and the heat deformation temperature, it is possible to obtain a halogenated vinyl polymer material having better physical properties while reducing the concentration of the impact modifier.

It fluctuates according to the kind of composition of the impact resistant modifier and the optimal concentration of hydrated alumina, and the desired implementation characteristic of this composition. For example, if the Izod impact strength of 2.0 has a sufficient value for an external weathering resistant compound, the data shown in FIG. 1 shows that: A composition having an impact modifier of 3 Phr is 24 Phr. It may contain a large amount of hydrated alumina and still maintain the same impact strength and have surprisingly improved weathering resistance and processability, as shown in Tables 6 and 7 below.

If it is also desired to improve the impact resistance, it is possible to obtain a desired impact strength and at the same time obtain desired weather resistance while slightly reducing the hydrated alumina strength.

As described above, the ratio of the impact modifier of the hydrated alumina can be 8: 1 or more, and the concentration of the hydrated alumina is preferably not greater than about 50 Phr. If this concentration is 50 Phr or more, the processing characteristics are lowered and it is difficult to distribute uniformly throughout the hydrated alumina polymer material.

D. Machinability

The addition of the finest particle size hydrated alumina to the above-mentioned hard PVC composition improves the weighting properties as evidenced by increased dynamic processing stability and reduced torque, material temperature and pressure. For example, a standard support composition containing 10 Phr of ultrafine particle size hydrated alumina exhibits an equilibrium torque of 1525 m-gram and a material temperature of 206 ° C., while the same composition without hydrated alumina is 1650 m-gram. Equilibrium torque of and material temperature of 208 ℃ are shown. In the same torque flowmeter test, the composition with 10 Phr of hydrated alumana had a 13% increase in thermal stability, and a stabilization time of the comparative composition was 19.6 minutes, with a stabilization time of 22.2 minutes. The same composition with 6 Phr of hydrated alumina shows an increase in thermal stability of 9% compared to the comparative composition (see Table 4).

The same composition as above, in addition to the torque flow meter test, is processed under a controlled condition using a Kraus-Maffei 25 mm conical twin screw test extruder equipped with a 2.5 inch, 40 mil strip die. The use of ultra-hydrated alumina reduces the torque and reduces the motor amperage or the extrusion pressure. This data is shown in Table 2.

A common problem in weather resistant hard PVC processing machines is the screw and barrel abrasion which is brought about by the polishing of titanium dioxide (moh hardness of about 6.5). It differs from very hard alumina (moh hardness about 9), and hydrated alumina is similar to calcium carbonate, which is relatively soft and has a mother hardness of about 3. Combining with ultrafine particle sized hydrated alumina can reduce the titanium dioxide concentration and consequently reduce the wear of the barrel and screw.

E. Weathering Resistance

The use of ultra-fine particle hydrated alumina, as described in the rigid PVC composition, has other advantages, which reduces the TiO ₂ concentration while improving weathering resistance. For example, a standard support composition containing ultrafine particle size hydrated alumina at various concentrations is prepared and extruded with a KN-25 test extruder. The results of the accelerated light stability test on the extruded sample with a fluorescent solar / black light (FSBL) light source showed that the light stability was improved by adding hydrated alumina (see Table 5).

The compositions of the other series are extruded in the same way and tested in the QUV fabric. This test also shows that the addition of ultrafine particle sized hydrated alumina improves the light stability. In this series of compositions, compositions containing 10 Phr of TiO ₂ and 6 Phr of hydrated alumina exhibited at least the same photostability as the comparative compositions containing no hydrated alumina and 12 Phr of TiO ₂ (see Table 6).

A long external weathering test was conducted with a hydrated alumina composition for 12 months. The white compound extruded strips were weathered at a 45 ° inclination angle in southern Arizona and the green compound extruded strips were weathered at 45 ° inclination in the paid Florida. The results showing the improvement are shown in Tables 7 and 8.

The weathering resistance test of Arizona, conducted on a hard PVC composition containing ultrafine particle sized hydrated alumina and calcium carbonate, showed that the composition containing calcium carbonate caused choking for yellowing than the comparative or hydrated alumina-containing composition. Turned out to be great. The reason why such calcium carbonate is not widely used for external compounds, especially coloring compositions that are harmful to the occurrence of choking phenomenon, is that the filler has the same properties as the cinger (see FIG. 3).

The variable altitude impact test (VHIT) is done with green extrusion strips prepared for the Florida weathering test. The impact result from the extruded sample containing hydrated alumina according to the present invention was the same as that of the comparative sample (see Table 8).

In addition to the ultrafine particle sized hydrated alumina and impact modifiers described above, the halogenated vinyl polymer compositions of the present invention also contain conventional compounding components such as stabilizers and fillers, and any additives such as pigments, lubricants, dyes, ultraviolet absorbers, plasticizers, and the like. It contains.

Usually, the ultrafine particle sized hydrated alumina is blended into a halogenated vinyl polymer composition by mixing a selected method of a hydrated alumina and an impact modifier in advance with a polymer resin or by mixing components with a resin.

Of course, it is necessary to disperse the hydrated alumina substantially uniformly throughout the mixture. In the composition for extrusion, the back pressure tends to decrease due to the addition of hydrated alumina, so care must be taken to apply sufficient shear force to the entire dispersion.

The general processing temperature and conditions should be maintained with the processing temperature below about 230 ℃. If the processing temperature is higher than this value, hydrated alumina may decompose slightly due to water loss.

Example 1

Prepare specimens for the Izod impact test using 35-40 mill sheets prepared at 325 ° F. for 5 minutes. The prepared sheets are cut into four 6 " x6 " sheets and the sheets are staggered.

The sample is press molded into 1/8 "plaque at 375 ° F. for 10 minutes at 3000 PSI f. Izod impact strength is measured by ASTM D-256 and physical properties are measured by the method described in ASTM-1784.

Torque Flowmeter Dynamic processing stability is measured using a Brabender, Plasti-Corder (C.W.Brabender, Hackensack, N.J.) electrothermal torque flowmeter equipped with a No. 6 bowl according to the conditions listed in the table.

The accelerated and jade weathering tests and the variable altitude impact test (VHIT) were both measured in an extruded strip extruded under the same conditions by a KM-25 test extruder equipped with a 2-1 / 2 ", 40 and strip die mixed in a strong mixer. did.

The extrusion conditions were # 1 and # 2 # 3 at 320 [deg.] F., 295 [deg.] F. 325 [deg.] F., die temperature at 380 [deg.] F., and screw speed at 20 rpm. The variable altitude impact test was measured according to the method described in ASTM D-3679. Jade and accelerated weathering tests were performed as follows. Outdoor Weathering Test—All samples were inclined at 45 ° and exposed south to consistency.

Fluorescent solar lamp / black light (FSBL)-The test sample is irradiated with ultraviolet rays for 100 hours, and the procedure of leaving for 68 hours in dark light is repeated.

QUV-Promoted Weathering Test—A sample G-Panel Co. (Ohido, Cleveland) was subjected to condensate at 50 ° C. for 2 hours at 50 ° C. and then irradiated with UV rays for 4 hours. Repeat with a device suitable for -53.

The composition is prepared as follows.

Composition "A" is used for the Izod impact test and the results are summarized in Tables 1, 2 and 3; Composition "B" is used for torque flow system stability test, extrusion test, variable altitude impact test and weathering test; The results are summarized in Tables 4, 5, 6, 7, and 8. Composition "C" is used for weathering resistance tests comparing hydrated alumina and calcium carbonate; This result is shown in Table 3. For green support compounds, non-choke grade titanium dioxide was used in place of the choking grade titanium dioxide used in the white support compound. In particular, unless otherwise described, the hydrated alumina was prepared by the precipitation method, and the average particle size was 0.5 mu.

The following table illustrates the effect of hydrated alumina on the various properties of rigid PVC materials.

TABLE 1

Synergistic effect of hydrated alumina and impact modifier

TABLE 2

Effect of Hydrated Alumina and Reinforced Impact Resistance Modifiers

TABLE 3

Effect of Particle Size and Filler Mold

TABLE 4

Effect of Hydrated Alumina on Dynamic Processing Stability (Ⅰ)

TABLE 5

Effect of Hydrated Alumina on FSBL (Ⅰ) Promoted Weathering Test

TABLE 6

Effect of Hydrated Alumina on QUV Promoted Weathering Test

TABLE 7

Effect of Hydrated Alumina on Weathering Resistance (1)

TABLE 8

Effect of Hydrated Alumina on Weathering Resistance (1) (2)

Example 2

In order to know the effect of hydrated alumina on the compositions prepared with or without the weather resistance modifier and plasticizer, a series of PVC compositions were prepared using the components in the proportions shown in Table 9. Each composition was evaluated by the accelerated weathering test (FSBL and QUV) described in Example 1, and the results are summarized in Table 9.

Each composition of this example is mixed, milled at 350 ° C. for 5 minutes and then press molded at 350 ° F. for 5 minutes to produce a 125 mil plaque. Yellowness index was measured by NACBETH ^R 1500 colorimeter.

It can be seen from the results reported in Table 9 that the composition containing the ultrafine particle sized hydrated alumina (average 0.5μ) showed better weathering resistance than the composition containing no ultrafine particle size. Such improvement in weathering resistance can be achieved in compositions prepared using impact modifiers or plasticizers, compositions prepared without using them, and compositions prepared using both impact modifiers and plasticizers. As a result shown in Table 9 it can be seen that the weathering resistance is improved by the impact modifier and the plasticizer used in the composition of the present embodiment, the weathering resistance of the composition is increased by the use of hydrated alumina having an average particle size of 0.5μ.

TABLE 9

Example 3

A series of polyvinyl chloride compositions are prepared using the component ratios listed in Table 10 and the effect of hydrated alumina on weathering resistance is evaluated. Using the accelerated weathering tests (FSBL and QUV) described in Example 1, the results obtained are summarized in Table 11.

Each composition of this example is mixed and then ground for 5 minutes at 350 ° F. Composition 1-5 is prepared by adding each component, and composition 6 is prepared by premixing each component of the impact modifier, stabilizer, processing aid, TiO ₂ and hydrated alumina, and then adding other components.

When the hydrated alumina having an average particle size of 0.5 mu and 0.9 mu is added to the polyvinyl chloride composition, it can be seen from the results shown in Table 11 that the weathering resistance is improved compared to the composition containing no hydrated alumina. In addition, the hydrated alumina having an average particle size of 0.5 mu increases the weathering resistance of the PVC composition containing the impact modifier, and the advantages thereof are the same as those previously added as a mixture even when the components of the composition are added individually. It can be seen.

TABLE 10

TABLE 11

QUV accelerated weathering test

Claims (7)

Vinyl Halide Polymer Halogenated vinyl polymer composition with improved weather resistance and processability, characterized by consisting of a hydrated alumina and a filler having an average particle size of 0.4-0.6 micron. The impact modifier resin according to claim 1, in order to form a synergistic composition with the hydrated alumina which increases the impact strength of the composition, wherein the ratio of the hydrated alumina and the impact modifier is 1: 2-4: 1. A composition comprising 1-15 parts. The composition of claim 2, wherein the impact modifier is present in an amount of 1 phr-15 phr, and the hydrated alumina is present in a weight ratio of 1: 2-8: 1 by weight of the impact modifier. A) impact modifier, b) an average particle of 0.4-0.6 micron, in a halogenated vinyl polymer material containing 1-15 parts per hundred impact modifier resins to form a synergistic composition that enhances impact resistance to the halogenated vinyl polymer material. A method of increasing the impact resistance of a vinyl halide polymer characterized by mixing hydrated alumina having a size. The method of claim 4, wherein the temperature is maintained at 285-325 ° F. upon mixing of the components. The method according to claim 4, wherein the weight ratio of the hydrated alumina and the impact resistance modifier is in the amount of 1: 2-8: 1. The method according to claim 4, wherein the weight ratio of the hydrated alumina and the impact modifier is added in an amount of 1: 1: 1-4: 1.

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