KR870001575B1 - Preparation of acrylate additives for improvement of properties - Google Patents

Abstract

The prepn. of the property improver comprises two processes. In the 1st process, the mixture of 40-80 wt.% of ion-exchanged water, 0.01- 0.2 wt.% of emulsifying agent, 3-30 wt.% of monomer and 0.01-0.1 wt.% of initiator is polymd. to give seed latex of particle size 0.02-0.05μ. In the 2nd process, the mixture of 80-200 wt.% of ion-exchanged water, 0.25-0.8 wt.% of emulsifying agent, 70-100 wt.% of monomer, 0.1-1 wt.% of initiator and 0.01-0.1 molecular regulating agent is polymd. with above seed latex to give the title compd. of particle size 0.1-0.15 .

Description

Method for producing acrylate-based physical modifier

1 is a graph showing the melt viscosity when the physical modifier according to the present invention is added and not added.

Figure 2 is a graph showing the 30 second shear modulus with and without the physical modifier according to the present invention using a Klash-Berg Torsion Meter.

3 is a spectrum showing the shear modulus with and without the physical modifier according to the present invention using the rheometric mechanical spectrometer model # 605.

The present invention relates to a method for producing an acrylate-based physical modifier. In more detail, the present invention is polymerized by the addition of an emulsifier, a small monomer and an initiator, and then polymerized with an emulsifier, an excess monomer, an initiator, a molecular weight modifier with a product prepared in the polymerization reaction in an emulsion state. It relates to a method for producing a modifier.

The physical property modifier of the present invention improves the moldability, processability and weatherability by mixing with a thermoplastic resin such as a vinyl chloride polymer, as well as the heat deformation temperature, hardness and tensile strength allowed when only the vinyl chloride resin and the impact modifier are mixed. Raise.

Therefore, the physical property improving agent of the present invention is prepared for use as a component of a thermoplastic resin such as vinyl chloride resin, rather than being used alone.

In general, when looking at the composition of the widely used vinyl chloride sheet is prepared by mixing the vinyl chloride resin and acrylate-based impact reinforcing material is excellent in impact strength, but poor in physical properties such as heat deformation temperature, hardness, tensile strength. On the other hand, in the case of mixing the acrylate polymer having a high glass transition temperature such as vinyl chloride resin and methyl methacrylate polymer, the opposite phenomenon appears in the physical properties.

In the present invention, an acrylate-based physical modifier was prepared to eliminate the above disadvantages.

Generally, impact modifiers used to increase the impact strength of vinyl chloride resins include acrylates, methyl methacrylate-butadiene-styrene (MBS), acrylonitrile-butadiene-styrene (ABS), and halogenated polyolefins. A system (POE system), an ethylene vinyl acetate system (EVA system), etc. are mentioned.

Among the impact reinforcing materials, the acrylate-based impact reinforcing material is used as a processing aid in the processing of vinyl chloride resin with the inherent weather resistance of the resin itself, and thus is widely used for the processing of vinyl chloride resin for various uses. However, since most of the acrylate-based impact reinforcing materials are composed of high-quality acrylates, the impact strength when mixed with vinyl chloride resin is markedly increased, but there is a significant drop in heat deformation temperature, hardness, tensile strength, especially heat deformation temperature. Bring.

In the present invention, as a result of the intensive efforts to eliminate the problems of the impact reinforcing material as described above, while maintaining the impact strength at the desired level when mixing with the vinyl chloride resin, while improving the heat deformation temperature and at the same time improve the processability of the resin and also weather resistance The present invention has been completed by preparing the acrylate-based physical modifier.

When the acrylate-based physical properties improver (hereinafter abbreviated as A-4) according to the present invention in more detail with reference to the role in the thermoplastic resin,

First, as shown in FIG. 1, when A-4 is added, the melt viscosity increases as compared with the case where only the vinyl chloride resin and the impact modifier are mixed. In sheet extrusion processing of vinyl chloride resin, an increase in melt viscosity means an increase in melt strength, and due to the increase in melt strength, sheet processing extrudeability is excellent.

The excellent melt strength can be perceived to some extent with the naked eye in roll-mill processing.

Second, the shear modulus curve changes due to the addition of A-4 as shown in FIG. In the case of thermoforming or vacuum forming, it is effective to process in the range of rubber flow region, that is, the modulus of 30-100Psi, which is processed by the addition of A-4 at 30-100Psi. The wider temperature range increases the time required between heating and processing, which facilitates heating and vacuum forming.

Third, Figure 3 is a RMS Chart (Rheometrics Mechanical Spectrometter Chart), which shows that the glass transition temperature (shown as a peak in the figure) moves toward the high temperature by the addition of A-4. This is a natural phenomenon that occurs because the glass transition temperature (T _g ) of A-4 is higher than that of vinyl chloride resin, which may provide clear evidence that the heat distortion temperature increases.

If A-4 is added too much, the impact strength drops sharply, so it is necessary to finely control the addition amount.

When the acrylate property modifier of the present invention is mixed at 5 parts by weight or less, the impact strength is improved, but the heat deformation temperature, hardness and tensile strength are decreased. In the case of mixing more than 50 parts by weight, the opposite phenomenon occurs.

In the manufacturing method of the present invention, the first step process is to adjust the size of the seed latex (seed latex) particle size into the reactor after the ion-exchanged water to add the emulsifier to start the stirring. When the internal temperature reaches 60-80 ° C with stirring, the monomer is added to the reactor and when the temperature rises to a stable state, an initiator is added to start the polymerization reaction. 0.3-2 hours after the addition of the initiator, one-step polymerization is completed, and the latex particle size is 0.02-0.05μ.

In the second step, the latex particle size of the first step is grown. Unlike the temporary addition in the first step, the monomer, ion-exchanged water, emulsifier, initiator, and molecular weight regulator are mixed in the pre-emulsion state and then in the reactor. Input is carried out continuously. Explaining this process, the ion-exchanged water is first introduced into the preemulsion tank, and the stirring is started as in step 1 by adding an emulsifier. Subsequent addition of the monomers followed by addition of the initiator forms a preemulsion.

When the preemulsion formed is pumped into the reactor, the monomers are polymerized with the products prepared in the first step and the grown latex particle diameters of which the particles grow are about 0.1-0.15 μm.

The two-stage process takes about 1-4 hours and completes the polymerization after 1 hour of aging.

In this way, the polymerized latex is diluted by adding ion-exchanged water so that the weight percentage of the solid content is 15-25%, and then the temperature is raised to 60-80 ° C, and then sulfuric acid, hydrochloric acid, aluminum sulfate, calcium chloride, sodium chloride, etc. The flocculant is flocculated by adding 0.1-5 parts by weight per 100 parts by weight of latex solids. The agglomerated polymerizer becomes an acrylate-based physical modifier having a particle size of 50-400 μ after dehydration and drying. The acrylate-based improver obtained in this way is appropriately mixed with thermoplastic resins, impact modifiers, other stabilizers, lubricants, etc. to suit the purpose of the final product. Harmonized thermoplastic resin sheets can be obtained.

Emulsifiers used in the present invention include sodium lauryl sulfate, sodium dodecyl sulfate, sodium dodecyl benzene sulfate, sodium octadecyl sulfate, sodium oleic sulfate, calcium dodecyl sulfate, calcium dodecylbenzene sulfate, potassium octadecyl sulfate, Potassium oleic sulfate, rosin and the like are used in amounts of 0.01-0.2 parts by weight in the first stage reaction and 0.25-0.8 parts by weight in the second stage reaction. The formation of a coagulation body or deterioration of the stability of the latex after the reaction, and the use of a larger amount than the above range makes the coagulation process difficult due to the finer particles of the latex and adversely affects the final physical properties.

Examples of the monomer used in the present invention include alkyl esters of acrylic acid having 1 to 8 carbon atoms and alkyl esters of methacrylic acid having 1 to 4 carbon atoms, specifically methyl, ethyl, propyl, isopropyl, butyl, 2-ethylhexyl ester of acrylic acid, Methyl, ethyl, propyl, isopropyl, butyl ester of methacrylic acid is mentioned.

Among them, butyl acrylate, 2-ethylhexyl acrylate, and ethyl acrylate, which have a relatively low glass transition temperature of the polymer, are used in the first stage reaction, and in the second stage reaction, methacryl having 1 to 4 carbon atoms of the alkyl group is used. Acid alkyl esters are used.

Its amount is preferably 3-30 parts by weight in the first stage reaction, 70-100 parts by weight in the second stage reaction.

The ion exchanged water used in the present invention is pure water having a metal ion concentration of 2 ppm or less via an ion exchanger.

Its use amount is 40-80 parts by weight in the first step, 80-200 parts by weight in the second step, the use of a small amount in the above range in each step is not uniform particle distribution due to the high heat of reaction in the first step reaction, two-step reaction In the high weight ratio of solids, heat transfer is difficult due to the high viscosity of the latex, which makes it difficult to maintain a constant temperature inside the reactor, and many scales or solids are formed. In addition, the use of a large amount of ion-exchanged water in the above range is too economical because it takes too long to increase the temperature in the reactor up to 80 ℃ not only decreases productivity but also requires a lot of heat. In addition, in the present invention, it is possible to completely eliminate the heat of reaction by adopting a continuous dosing method without using a temporary dosing method in the second step reaction, and it is easy to control the latex particle size and the particle size distribution by adjusting the dosing time.

Initiators used in the present invention include acetyl peroxide, benzoyl peroxide, cumyl peroxide, t-butyl peroxide, t-butyl hydroperoxide, cumyl hydroperoxide, 2, 2'-azobisisobutylonitrile, Ammonium persulfate, calcium persulfate and the like are preferably used at 0.01-0.2 parts by weight in the first step and 0.1-1 parts by weight in the second step.

Molecular weight regulators used in the two-step reaction include t-butyl disulfide, butylamine, triethylamine, t-butyl disulfide, carbon tetrachloride, carbon tetrabromide, n-butyl mercaptan, t-butyl mercaptan, t- Dodecyl mercaptan (TDDM) and the like are usually used in amounts of 0.01-01 parts by weight.

Example 1

First stage

After adding 40.4 parts of ion-exchanged water to the reactor, 0.05 part of sodium tauryl sulfate was added to start stirring. In addition to stirring, when the internal temperature of the reactor reaches 80 ° C., 0.2 parts of ethyl acrylate and 0.2 parts of ammonia ohmsulfate are added to polymerize for 1 hour.

2nd step

After completion of the first stage reaction, 110 parts of ion-exchanged water, 0.4 part of tarium lauryl sulfate, and 95 parts of methyl methacrylate were added to the preemulsion tank to form a milky preemulsion, and then pumped into the reactor for 1 hour. Reaction is carried out with the reaction product of the first step by using a continuous feed at a constant rate. After one hour of aging, the casting is completely finished.

At this time, the latex particle size is about 0.1-15μ, pH about 2.7-3.0. 100 parts by weight of ion-exchanged water was added to 100 parts by weight of the latex thus obtained, and when the diluted latex mixture reached 90 ° C. while heating and stirring, 12 ml of 10% calcium chloride solution was added to agglomerate the latex, and the temperature was raised to 95 ° C. To form solid particles.

Subsequently, the mixture is cooled to room temperature, dehydrated by centrifugation, dried in a speed dryer, and an acrylate physical modifier is obtained.

Hereinafter, the following tests were carried out to evaluate various physical properties of the acrylate-based physical modifier prepared according to the above method.

[Test Example 1]

100 parts by weight of vinyl chloride resin (average molecular weight 100,000), 10 parts by weight of the acrylate resin obtained above, 20 parts by weight of acrylate impact modifier, 3.0 parts by weight of tin maleate (TMA) as a heat stabilizer, and 0.5 parts by weight of lubricant (PA-5200). The parts were mixed and mixed for 5 minutes in a mixture at 190 ° C., and then specimens were prepared using a 190 ° C. press to measure various physical properties by the ASTM method. The measurement results are shown in Table 1.

[Test Example 2]

Physical properties were measured by performing the same method as Test Example 1 using an acrylate physical modifier prepared in Example 1 using sodium dodecyl sulfate instead of sodium tauryl sulfate. The measurement results are shown in Table 1.

[Test Example 3]

It was carried out in the same manner as in Test Example 1 using an acrylate physical modifier prepared using butyl acrylate instead of ethyl acrylate used in the first step of Example 1. The measurement results are shown in Table 1.

[Test Example 4]

The physical properties were measured in the same manner as in Test Example 1 using an acrylate physical modifier prepared using ethylhexyl acrylate instead of the ethyl acrylate used as the monomer in Step 1 of Example 1. The measurement results are shown in Table 1.

[Test Example 5]

Butyl acrylate instead of ethyl acrylate used in step 1 of Example 1, 45 parts of methyl methacrylate, 40 parts of styrene in the second step was carried out in the same manner as in Test Example 1 using a physical modifier Was measured. The measurement results are shown in Table 1.

[Test Example 6]

Physical properties were measured in the same manner as in Test Example 1 using a physical modifier prepared using methyl acrylate instead of ethyl acrylate used as a monomer in Example 1 step. The measurement results are shown in Table 1.

TABLE 1

The first table has the following meanings.

1) When butyl acrylate with low glass transition temperature (Tg) is used instead of ethyl acrylate in the first step, the Izod impact strength is somewhat higher but the heat deformation temperature or tensile strength is lower.

2) If no monomer of high substance is used at all, the level of heat deformation temperature is very small, but impact strength is drastically decreased.

Claims (5)

Sidratex (40% by weight) of ion-exchanged water, 0.01-0.2 parts by weight of emulsifier, 3-30 parts by weight of monomer and 0.01-0.1 parts by weight of initiator are polymerized to make rubber latex particle diameter of 0.02-0.05μ latex) the first step of controlling the particle size, 80-200 parts by weight of ion-exchanged water, 0.25-0.8 parts by weight of emulsifier, 70-100 parts by weight of monomer, 0.1-1 parts by weight of initiator, 0.01-0.1 parts by weight of molecular weight regulator After mixing externally in a culled state, it is continuously introduced into a reactor and polymerized with the products prepared in the first step to perform a second step of emulsion polymerization to grow particles having a latex particle diameter of 0.1-0.15 μ. Method for producing an acrylate-based physical property modifier, characterized in that. The method of claim 1, wherein the emulsifier is sodium lauryl sulfate, sodium dodecyl sulfate, sodium dodecyl benzene sulfate, sodium octadecyl sulfate, sodium oleic sulfate, calcium dodecyl sulfate, calcium dodecylbenzene sulfate, potassium octadecyl sulfate, Potassium oleic sulfate, a method for producing an acrylate-based physical modifier, characterized in that the rosin. The method for producing an acrylate-based physical modifier according to claim 1, wherein the monomer is an acrylic acid alkyl ester having 1 to 8 carbon atoms and a methacrylic acid alkyl ester having 1 to 4 carbon atoms. The method of claim 1, wherein the monomer of the first step is butyl acrylate, 2-ethylhexyl acrylate, ethyl acrylate. The method of claim 1, wherein the second monomer is a methacrylic acid alkyl ester having 1 to 4 carbon atoms.

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