WO2005105909A1

WO2005105909A1 - A hydrotalcite-based composite heat stabilizer for chlorine-containing high polymer

Info

Publication number: WO2005105909A1
Application number: PCT/CN2004/001113
Authority: WO
Inventors: Xue Duan; Dianqing Li; Yanjun Lin
Original assignee: Beijing University Of Chemical Technology
Priority date: 2004-04-29
Filing date: 2004-09-28
Publication date: 2005-11-10
Also published as: CN1252159C; CN1590437A

Abstract

The present invention relates to a hydrotalcite-based composite heat stabilizer for chlorine-containing high polymer which is made up of hydrotalcite, calcium soap and zinc soap according to a certain proportion. The main ingredient of the composite heat stabilizer is [Mg2+1-xA13+X(OH)2]CO32-X/2 . mH2O (0.2≤x≤0.33; 0≤m≤2). The composite heat stabilizer has better heat stabilitz for PVC and other chlorine-containing higher polymer, is toxicless, pollution-free, low cost, abundant raw material and so on.

Description

Technical field of hydrotalcite-based chlorine-containing polymer composite heat stabilizer

The present invention relates to a hydrotalcite-based chlorine-containing polymer composite thermal stabilizer, and particularly to a calcium / zinc compound-containing hydrotalcite-based chlorine-containing polymer composite thermal stabilizer. Background technique

PVC resin has the characteristics of difficult to burn, high mechanical properties, low price, rich raw material source, mature manufacturing process, etc. It is widely used in construction, telecommunications, transportation, electronics, chemical industry, packaging and other industries. Two major types of general-purpose thermoplastics. However, the thermal stability of PVC itself is very poor. Its flow temperature is 136 ° C and its decomposition temperature is 140 ° C. The difference between the two is only 4 ° C, which brings great difficulties to processing and use. Therefore, a certain amount of heat must be added. stabilizer. Other chlorine-containing polymers also undergo autocatalytic reactions to de-HC1 under heat or ultraviolet radiation, reducing various properties of the material. Heat stabilizers are one of the essential wife additives for the processing of PVC and other chlorine-containing polymers. At present, thermal stabilizers can be mainly divided into basic lead salts, metal soaps, organic tins, rare earths and composite stabilizers according to their chemical structure. With the strengthening of environmental protection awareness, PVC heat stabilizers are developing in the direction of low toxicity, pollution-free and high efficiency. It is of great significance to research and develop a new generation of green and environmentally friendly PVC heat stabilizers.

Hydrotalcite, also known as Layered Double Hydroxides (LDHs), is a typical anionic layered compound with a typical molecular composition of Mg ₆ Al ₂ (0H) ₁₆ C0 ₃ · 4H ₂ 0. Because the surface of the laminate is alkaline, it can absorb the aci released from the pyrolysis of PVC and other chlorine-containing polymers, thereby inhibiting its autocatalytic decomposition. In addition, it is believed that its thermal stability mechanism is due to LDHs. The exchangeability of interlayer ions allows interlayer C0 ₃ ² to exchange with HC1 entering the interlayer, so as to absorb HC1, stabilize PVC and other chlorine-containing polymers. Hydrotalcite-filled PVC is compounded with other thermal stabilizers, such as organic, lead, or zinc salts, to further improve the thermal stability of PVC. Document [1]: United States Patent Uniform States Patent 4299759 (1981). Kyowa Chemical Co., Ltd. took the lead in 1980 to conform to the following formula: M _gl _ _x Al _x (OH) ₂ A _{x / n} ⁿ --mH ₂ 0 (0 <x <0.5) hydrotalcite is filled into PVC to be used as a heat stabilizer. As a result, the heat stabilization effect of PVC is significantly improved. When adding 1 part Mg to 100 parts PVC. . ₇ Al. ₃ (OH) ₂ (C0 ₃ ). . ₁₅ · 0. 55H ₂ 0, 0. 75 parts of zinc stearate and 0.3 parts of organotin, the heat stability time of PVC can be extended to 62 minutes at 180 ° C. Under the same conditions, using 2 parts of stearic acid / zinc stearate thermal stabilizer, the thermal stabilization time is only 38 minutes.

Literature [2]: Hua Youqing et al. [Research on a new type of polyvinyl chloride heat stabilizer-hydrotalcite, polyvinyl chloride, 2001, 6: 42-44] found that 2 parts of Mg / Al = 2 were used alone The hydrotalcite has a decomposition temperature of 264 ° C, and after mixing the hydrotalcite and the organotin heat stabilizer at a ratio of 1: 1, 2 mixed heat stabilizers are added to 100 parts of PVC, and the initial decomposition temperature is increased to 279. ° C, increased by 15 ° C. '

Literature [3]: Nissan Ferro Organic Chemicals of Japan found that perchloric acid and hydrotalcite have a better synergistic effect (JP59140261, 1984). They combined 1mol of hydrotalcite and 0.001-2mol of perchloric acid into 100 parts of PVC resin and added 0.0001-100 parts of the composite thermal stabilizer, which can significantly improve the thermal stability of PVC. For example, adding 100 parts of PVC to 0.5 parts of barium stearate, 0.2 parts of lead salt, 0.5 parts of hydrotalcite / perchloric acid composite thermal stabilizer, the stability time can be reached at 180 ° C 90 minutes.

In the above literatures, hydrotalcite is compounded with other thermal stabilizers, which overcomes the shortcomings of using hydrotalcite as a thermal stabilizer alone, which has poor initial colorability. However, most of them use toxic elements such as lead and tin, which is not conducive to the development of hydrotalcite completely replacing the existing expensive or toxic thermal stabilizers. Summary of the invention

The purpose of the present invention is to overcome the shortcomings of the existing hydrotalcite-based chlorine-containing polymer composite heat stabilizers containing toxic elements such as lead and tin, and provide a hydrotalcite-based chlorine-containing polymer composite heat that does not contain toxic elements. stabilizer. The chlorine-containing polymer heat stabilizer provided by the present invention is a mixture, and its components and contents are: hydrotalcite: 10-82%

Calcium soap: 14-85%

Zinc soap: 1-47%;

The more preferred ratio is:

Hydrotalcite: 18-57%

Calcium soap: 35-75%

Zinc soap: 4-19%

The above percentages are all mass ¾ ■ fractions. The three components are thoroughly mixed to obtain a chlorine-containing polymer composite thermal stabilizer.

The calcium soap used in the present invention is one of calcium stearate, calcium octoate, calcium laurate, calcium palmitate, calcium oleate, calcium benzoate, and maleic acid, preferably stearic acid and lauric acid. Calcium and calcium benzoate.

The zinc soap used in the present invention is one of zinc stearate, zinc caprylate, zinc laurate, zinc palmitate, catalole oleate, zinc benzoate, and zinc maleate. Zinc stearate and zinc laurate are preferred. And zinc benzoate.

The hydrotalcite used in the present invention is a magnesium-aluminum hydrotalcite whose interlayer anion is carbonate, in which the molar ratio of Mg ²⁺ / Al ³⁺ satisfies a ratio of 2-4: 1. Its composition should satisfy the following general formula: [Mg ² V _x Al ³⁺ _x (OH) ₂ ] C0 ₃ ² " _{x / 2} -mH ₂ 0, where 0.2 <x <0.33; (Km 2. This hydrotalcite is best It is surface modified by organics, which is good for it in polymers ^ :.

The hydrotalcite used in the present invention can adopt a variable pH method (also known as a single drop method or a high supersaturation method), a constant pH method (also known as a double drop method or a low supersaturation method), and nucleation / crystallization Co-precipitation methods such as isolation method and urea method, or can be prepared by methods such as hydrothermal synthesis method and roasting reduction method.

In order to obtain a fine particle size, uniformly dispersed hydrotalcite, the present invention employs a nucleation / crystal separation, this method has a fine paradox is described in Chinese Patent No. ^{^{^001321455:}} specific steps are: magnesium The salt and aluminum salt are mixed into a mixed salt solution according to the ratio of Mg ²⁺ / Al ³⁺ = 2- 4: 1 so that the concentration of Mg ²⁺ is 0.4- 2. Omol / L; NaOH or K0H and soluble carbonic acid Salt press n (C0 ₃ ² —) / n (Al ³⁺ ) = 1. 6-2. 5, n (OH—) / [n (Mg ²⁺ ) + n (Al ³⁺ )] = 1.4 The ratio of -2.2 is formulated into a mixed solution, which has the same volume as the mixed salt solution. The soluble carbonate may be any of Na ₂ C0 ₃ , K ₂ C0 ₃ , and (M ₄ ) ₂ C0 ₃ . The two solutions are rapidly mixed in a rotating liquid film reactor, and the slurry obtained after mixing is crystallized under reflux at 100 ° C for 6-10 hours, the precipitate is washed to pH «7, and filtered to obtain a hydrotalcite filter cake, and dried water The talc filter cake gives hydrotalcite powder. If you want to obtain surface-modified hydrotalcite powder, add the washed and filtered filter-cake to about 23-35 times the solid content of the filter cake, heat up to 80-100 ° C, and add 4-7% solid content The stearic acid was stirred and reacted for 2-5 hours. After drying, an organic hydrotalcite powder was obtained on the surface. Prepared by the method of particle size distribution of the hydrotalcite is ^{2 0nm-} 120nm.

The composite heat stabilizer provided by the present invention is mainly used in chlorine-containing polymers, usually polyvinyl chloride, chlorinated polyethylene, chlorinated polyvinyl chloride, vinyl chloride-ethylene copolymer, vinyl chloride-acid copolymerization. Things. The amount of the heat stabilizer (based on parts by mass) is preferably 0.1 to 10 parts in 100 parts of the chlorine-containing polymer, and the preferred amount is 3 to 6 parts. ·

The static thermal aging experiment was performed on polyvinyl chloride and chlorinated polyethylene (CPE) added with the composite thermal stabilizer, and the results show that the composite thermal stabilizer provided by the present invention can effectively improve PVC and other chlorine-containing polymers. Thermal stability. Under the environment of 180 ± 1 ° C, PVC and chlorine-containing polymers show good initial colorability, and the heat stability time can reach more than 80-220 minutes. PVC and chlorine-containing polymers without adding heat stabilizers Its thermal stability time is only 6-10 minutes. detailed description

Examples 1-9

Weigh 48.15g MgS0 ₄ (0.4mol) and 66.64gAl ₂ (S0 ₄ ) ₃ · 18Η ₂ 0 (0.1mol), mix and add deionized water to 500 ml to prepare Mg ²⁺ / Al ³⁺ Mixed salt solution with a molar ratio of 1; weigh 42.4g of Na ₂ C0 ₃ (0.4 mol) and 38.4g of NaOH (0.96 mol) and add deionized water to 500 ml to prepare a mixed alkali solution, alkali solution The molar concentrations of C0 ₃ ² — and 0H satisfy n (C0 ₃ ^2- ) / n (Al ³⁺ ) = 2, n (OH ") / [n (Mg ²⁺ ) + n (Al ³⁺ )] = 1.6 ₀ Quickly mix in the reactor. The slurry obtained after mixing is crystallized at reflux for 6 h at 100 ° C. The precipitate is washed to pH «7 to obtain a hydrotalcite filter cake. Add about 30 times the solid content of the filter cake and raise the temperature to 80 ° C, adding stearic acid with a solid content of 5% and stirring for 2 hours. After drying, a hydrotalcite powder with a surface-modified magnesium / aluminum ratio of 2 can be obtained.

According to the above method, the amount of MgS0 ₄ and A1 ₂ (S0 ₄ ) ₃ · 18H ₂ 0 is changed so that the molar ratio of Mg ²⁺ / Al ³⁺ in the mixed solution is 2.5, 3, 3.5, and 4 to obtain magnesium / aluminum. Surface modified hydrotalcite powders with ratios of 2.5, 3, 3.5, and 4, respectively.

The above-mentioned hydrotalcite was mixed with 4-stearic acid and zinc stearate in the proportions of 30%, 60%, and 10%, respectively, to obtain a chlorine-containing polymer composite thermal stabilizer. Add different amounts of composite thermal stabilizers to 100 parts of PVC or CPE, and then add 50 parts of diisooctyl phthalate (DOP). Mix on a SSR-Z4 plastic experimental machine at 14CTC for 10 minutes. At 100 ° C, a sheet with a thickness of 1 cm was pressed and cut into 1 cm X 1 cm test pieces. The test piece was placed in a thermal aging test box at 180 ° C and 1 ° C for static aging experiments. The time when the test piece started and the black decomposition point appeared as the thermal stabilization time. The results are shown in Table 1:

Table 1 Example Mg / Al polymer (100 parts) Thermal stabilizer (parts) Thermal stabilization time (minutes)

1 2 PVC 0 7

2 2 CPE 0 9

3 2 PVC 1 160

4 2 PVC 2 200

5 2.5 PVC 2 190

6 3 PVC 2 170

7 3 CPE 5 190

8 3.5 PVC 8 180

9 4 CPE 2 90 Examples 10-15

Change the composition and ratio of the composite heat stabilizer, add to 100 parts of PVC or other chlorine-containing polymers at different dosages, add 50 parts of D0P, mix and tablet, and perform in a 180 ± rC heat aging test box The static aging test results are shown in Table 2:

Table 2

Claims

Claim

1. A chlorine-containing polymer heat stabilizer, which is a mixture of hydrotalcite, calcium soap and zinc soap. The proportion of each component is:

Hydrotalcite: 10-82%

Calcium soap: 14-85%

Zinc soap: 1-47%

The above percentages are all mass percentages;

Among them, calcium soap is one of 4 stearic acid, 4 caprylic acid, 4 lauric acid, 4 palmitate, calcium oleate, calcium benzoate, and maleic acid hook;

Zinc soap is one of zinc zinc acid, zinc octoate, zinc laurate, zinc palmitate, catalole oleate, zinc benzoate, zinc maleate;

7j talc ^ ^ anion is carbonate-magnesium aluminum hydrotalcite: its Mg ²⁺ / A 1 ³⁺ molar ratio should meet 2-4: 1, its composition should meet the following general formula:

· MH ₂ 0, where 0.2 <x <0.33; (m <2.

2. A chlorine-containing polymer heat stabilizer according to claim 1, wherein the proportion of each component is:

Hydrotalcite: 18-57%

Calcium soap: 35-75%

Zinc soap: 4-19%

The above percentages are mass percentages;

Calcium soap is calcium laurate, lauric acid or calcium benzoate; zinc soap is zinc laurate, zinc laurate or zinc benzoate; hydrotalcite is a surface modification of organic matter with a particle size of 20nm-120nm7j talc.

3. A chlorine-containing polymer heat stabilizer according to claim 1, characterized in that the addition amount of the chlorine-containing polymer is 0.1-10 per 100 parts by mass of the chlorine-containing polymer. Parts by mass.

4. A chlorine-containing polymer heat stabilizer according to claim 1, characterized in that the amount of the chlorine-containing polymer added is 3-6 per 100 parts by mass of the chlorine-containing polymer. Shield portion.