CN101659759B - Organic-inorganic composite optothermal stabilizer, polyvinyl chloride prepared by using same and preparation method thereof - Google Patents

Abstract

The invention discloses an organic-inorganic composite photothermal stabilizer, a preparation method thereof and its application in polyvinyl chloride. The main components of the organic-inorganic composite photothermal stabilizer include 2-hydroxy-4-methoxy-5-sulfonic acid-benzophenone (BP-4), hydrotalcite (LDH), coupling agent and free radical capture agent. The preparation method of the photothermal stabilizer is as follows: first, put BP-4 and LDH after roasting pretreatment into the reactor according to the proportion, add water to prepare an aqueous solution, carry out anion exchange reaction, and make an organic-inorganic compound, and then put The composite is coupled and ultrasonically treated to prepare an organic-inorganic composite photothermal stabilizer. The light stability of polyvinyl chloride products containing this stabilizer has been greatly improved, and its thermal processing performance has also been significantly improved.

Description

Organic-inorganic composite photothermal stabilizer, polyvinyl chloride prepared therefrom and preparation method

technical field

The invention relates to the technical field of polymers, more specifically to a light and heat stabilizer for polyvinyl chloride, as well as a preparation method and application of the light and heat stabilizer.

technical background

Polyvinyl chloride (PVC) materials are prone to photodegradation under ultraviolet light, which leads to changes in their physical and chemical properties, such as darker color, brittle material and chalky surface, etc., and eventually loses its use value. The conventional method of anti-ultraviolet aging of polymer materials is to add a certain amount of organic ultraviolet light stabilizers, such as phenyl salicylate, o-hydroxybenzophenone, o-hydroxytriazoles and triazines, to the material body. Although these light stabilizers have a certain protective effect on polymers, their absorption of ultraviolet light is still not ideal. It has a small molecular weight, is easily soluble in water, and is easy to migrate. When used outdoors for a long time, it will be gradually lost due to surface volatilization and extraction by rainwater and other liquids, resulting in a greatly reduced light stabilization efficiency in the material. Finding and developing new light stabilizers with better light stabilizing effects is still a research hotspot in this field.

2-hydroxy-4-methoxy-benzophenone-5-sulfonic acid (2-hydroxy-4-methoxy-benzophenone-5-sulfonic acid, referred to as BP-4) is an anionic benzophenone photo Stabilizer, in the ultraviolet band, has stronger absorption than phenyl salicylate. However, its stability is poor. When heated to about 140°C, this stabilizer will turn into a brown liquid. When heated to 190°C, its thermal weight loss has reached 40%. When mixed with PVC and other additives and processed at 180°C, PVC instantly changes color and degrades. Therefore, BP-4 is currently mainly used in sunscreen cosmetics such as sunscreen cream, cream, honey, lotion, oil, etc. that do not require high thermal performance. If you want to use BP-4 as a UV stabilizer for PVC, you must first solve the problem of its thermal stability.

Hydrotalcite (Layered Double Hydroxides, abbreviated as LDH) is an important class of anionic layered compounds. Under certain conditions, new anions can be inserted into the interlayer to replace the original anions by means of ion exchange, so that the structure and composition are corresponding. The change.

Utilizing the adjustable structure and composition of hydrotalcite, a new type of light stabilizer can be prepared. For example, Duan Xue and others inserted the anion of 5-benzotriazole-4-hydroxy-3-isobutyl-benzenesulfonic acid into the nucleation/crystallization isolation method, and synthesized it with the full back-mixing explosive instantaneous nucleation technology The interlayer structure of the hydrotalcite precursor (see CN99119385.7 for the preparation method) was used to prepare an ultraviolet light stabilizer with an intercalation structure. The stabilizer has an ultraviolet light absorption rate of more than 90% for the 280-370nm band, and has good thermal stability. It can be used for light protection of polypropylene, polycarbonate, acrylonitrile-butadiene-styrene copolymer and polyurethane. He et al. (Journal of Chemistry of Solids, 2004, 65, 395-402) inserted 2-hydroxy-4-methoxy-5-sulfonic acid benzophenone (BP-4) into water synthesized by co-precipitation The precursor of talc, the hydrotalcite/BP-4 intercalation compound was prepared, which effectively solved the toxicity problem of BP-4 in direct contact with the skin, but there is no report about the performance and application of this compound in other aspects. The common point of the above methods is that they all need to use the hydrotalcite precursor prepared by a special method. The complicated preparation process and the further increased cost of use have greatly hindered the practical application and promotion of this type of light stabilizer in industry.

In addition, hydrotalcite is an inorganic material and has poor compatibility with polyvinyl chloride. If it is directly applied to this type of polymer material, the mechanical properties of the polymer material will decrease due to phase separation.

In view of this, the research and development of a photothermal stabilizer with higher heat resistance, higher compatibility with organic polymer compounds, and polyvinyl chloride products prepared from it has higher light stability, mechanical properties and good thermal processing properties , is a common problem faced by scientific and technological workers in their field.

Contents of the invention

The purpose of the present invention is to provide an organic-inorganic composite photothermal stabilizer and preparation method with strong operability, low preparation cost and excellent comprehensive performance. The easy migration of the agent, poor extraction resistance, easy volatilization, poor compatibility with organic substrates, low light stabilization efficiency, poor thermal stability, etc., greatly improve the anti-ultraviolet aging performance and thermal processing stability of the product.

The idea of the present invention is to first use the exchangeability of ions between hydrotalcite layers, and directly insert 2-hydroxy-4-methoxy-5-sulfonic acid benzophenone anion (BP-4) through a new preparation method Between the layers of hydrotalcite, an organic-inorganic composite is prepared, so that it has both the excellent properties of the two substances. On the one hand, it has high light protection efficiency, on the other hand, it has low migration rate and long-term stability. The second step is to carry out special treatment on the prepared compound to improve its heat resistance and compatibility with organic polymer compounds, so as to meet the requirements of higher light stability, mechanical properties and good thermal processing of polyvinyl chloride products. Performance requirements, while reducing preparation and use costs.

The concrete technical scheme that realizes the above-mentioned purpose of the present invention is as follows:

Organic-inorganic composite photothermal stabilizer for polyvinyl chloride (PVC), its raw material composition mainly contains 2-hydroxy-4-methoxyl-5-sulfonic acid benzophenone (BP-4), hydrotalcite ( LDH), coupling agent and free radical scavenger, wherein the weight content ratio of hydrotalcite and 2-hydroxy-4-methoxyl-5-sulfonic acid benzophenone is 0.5～10, coupling agent and free radical scavenger The weight content of the agent is respectively 0.2%-5% and 0.5%-10% of the total weight of talc and 2-hydroxy-4-methoxy-5-sulfonic acid benzophenone.

In the above technical scheme, the coupling agent is selected from titanate coupling agents and silane coupling agents, either one of them, or a mixture of two or more of them; the hydrotalcite can be natural water Talcite, also can be artificial hydrotalcite, selects natural hydrotalcite to reduce production cost, should preferably select natural hydrotalcite for use; Described free radical scavenger preferably selects the compound that contains following structural unit:

Wherein R ₁ is a group containing 1,1,2,2,-tetramethylpiperidine ring.

The preparation of the above-mentioned organic-inorganic composite photothermal stabilizer mainly includes the following steps:

(1) Put a certain proportion of 2-hydroxy-4-methoxy-5-sulfonic acid benzophenone and calcined hydrotalcite into the reactor and add water to make an aqueous solution, and carry out the process at 50-100°C Anion exchange reaction (that is, intercalation reaction), after sufficient reaction, the organic-inorganic composite is obtained by separation, washing and drying;

(2) After fully mixing the organic-inorganic composite prepared in step (1) with a certain amount of coupling agent, place it in water or ethanol, add a certain amount of free radical scavenger, apply ultrasonic irradiation, and make the composite Fully interact with the free radical scavenger, and obtain an organic-inorganic composite photothermal stabilizer through filtration, washing and drying.

In the preparation method of the above-mentioned organic-inorganic composite photothermal stabilizer, the hydrotalcite that has been calcined is hydrotalcite that has been calcined at 300-800°C for 1-10 hours; (5-250kW/m ³ ) irradiation for 10-30 minutes; the frequency of the ultrasonic wave is 20kHz; the anion exchange reaction (ie intercalation reaction) is reacted at 50-100°C for 10-50 hours.

The polyvinyl chloride prepared by the above-mentioned organic-inorganic composite light and heat stabilizer is composed of main components, in parts by weight:

The organic-inorganic composite photothermal stabilizer provided by the present invention has very excellent comprehensive performance, and the principle of its excellent comprehensive performance is that after the hydrotalcite is roasted at high temperature, impurities and small molecule volatiles are removed, and the hydrotalcite crystal is Activation facilitates ion exchange. After fully reacting with BP-4 in aqueous solution for a certain period of time, BP-4 can be fully exchanged with carbonate ions in natural hydrotalcite to obtain an ideal BP-4/hydrotalcite organic-inorganic composite. Then through surface coupling treatment, the compatibility between the compound and the polymer matrix is improved. Finally, the surface-treated compound interacts with the free radical scavenger under the action of ultrasound, and an organic-inorganic composite photothermal stabilizer with excellent comprehensive performance is obtained.

The application results show that the PVC material prepared by adding the organic-inorganic composite photothermal stabilizer provided by the invention, compared with the prior art, the UV stability of the material is significantly improved, the long-term retention rate of mechanical properties is improved, and the thermal processing stability is also improved. Significantly improved. The reasons for this are:

1. Insert 2-hydroxy-4-methoxy-5-sulfonic acid benzophenone into the hydrotalcite layer, combining the UV shielding function of hydrotalcite and 2-hydroxy-4-methoxy-5 - The absorption function of sulfonic acid benzophenone to ultraviolet light makes the light protection efficiency of the composite stabilizer significantly enhanced, and the addition of the free radical scavenger can also capture a part of free radicals, further improving the light stability of the polymer matrix. At the same time, the formation of the intercalation structure reduces the easy loss of BP-4 and improves the long-term stability of the material.

2. The addition of the coupling agent improves the compatibility between the compound and the polymer matrix, which is beneficial to the good dispersion of the organic-inorganic photothermal stabilizer in the matrix, and is beneficial to the improvement of the mechanical properties.

3. The addition of the free radical scavenger passivates the thermal degradation activation point generated by the interaction between the organic-inorganic compound and the matrix resin, consumes active free radicals, and improves the thermal processing stability of the polyolefin material containing the organic-inorganic compound sex.

The polyvinyl chloride prepared by the organic-inorganic composite photothermal stabilizer can be used to make various products such as PVC pipes, profiles, and plates, and the long-term retention rate of the comprehensive properties of the products can be greatly improved.

specific embodiment

The present invention will be specifically described below with reference to the embodiments, so that those skilled in the art can understand the present invention. It is necessary to point out here that the embodiments are only used to further illustrate the present invention, and cannot be interpreted as limiting the protection scope of the present invention. Those skilled in the art can make non-essential improvements to the present invention according to the above-mentioned content of the present invention And adjustments should still belong to the protection scope of the present invention.

In the following examples, unless otherwise specified, the percentages involved are all percentages by weight, and the parts involved are all parts by weight (phr).

Examples of organic-inorganic composite photothermal stabilizers are given below.

Example 1:

The natural hydrotalcite (LDH) was calcined at about 300°C for about 8 hours. Weigh 5 phr of the calcined product and 5 phr of 2-hydroxy-4-methoxy-5-sulfonic acid benzophenone (BP-4) into 20 phr of water. Stir well, react at about 80°C for about 40 hours, filter, wash and dry the product to obtain an organic-inorganic composite, and fully mix the composite with 0.2% titanate coupling agent by weight of the composite. Suspend the coupling-treated organic-inorganic composite and 0.5% free radical scavenger by weight of the composite in water, apply ultrasonic irradiation for about 10 minutes, the frequency of ultrasonic is 20kHz, and irradiate according to the material 200kW/ ^m3 , ultrasonic treatment After the completion, the product is filtered, washed and dried to obtain the desired organic-inorganic composite photothermal stabilizer. Recorded as organic-inorganic composite photothermal stabilizer I.

Example 2:

The artificial hydrotalcite (LDH) is calcined at about 600°C for about 3 hours. Weigh 5phr of the calcined product and 10phr of 2-hydroxy-4-methoxy-5-sulfonic acid benzophenone (BP-4) into 25phr of water. Stir well, react at about 100°C for about 10 hours, filter, wash and dry the product to obtain an organic-inorganic compound. The compound was thoroughly mixed with 3% titanate coupling agent and silane coupling agent (mass ratio 1:1). Suspend the coupled organic-inorganic compound and 5% free radical scavenger in ethanol, apply ultrasonic irradiation for about 20 minutes, the frequency of ultrasonic is 20kHz, and irradiate according to the material 100kW/m ³ , after the ultrasonic treatment is completed, the The product is filtered, washed and dried to obtain the desired organic-inorganic composite photothermal stabilizer. Recorded as organic-inorganic composite photothermal stabilizer II.

Example 3:

The natural hydrotalcite (LDH) is calcined at about 800°C for about 3 hours. Weigh 10phr of the calcined product and 2phr of 2-hydroxy-4-methoxy-5-sulfonic acid benzophenone (BP-4) into 25phr of water. Stir well, react at about 50°C for about 50 hours, filter, wash and dry the product to obtain an organic-inorganic compound. Mix this compound well with 5% silane coupling agent. Suspend the coupled organic-inorganic compound and 10% free radical scavenger in water, apply ultrasonic irradiation for about 30 minutes, the frequency of ultrasonic is 20kHz, and irradiate according to the material 50kW/ ^m3 . After the ultrasonic treatment is completed, the The product is filtered, washed and dried to obtain the desired organic-inorganic composite photothermal stabilizer. Recorded as organic-inorganic composite photothermal stabilizer III.

The examples and test results of the polyvinyl chloride containing the photothermal stabilizer provided by the present invention are given below.

Example 1:

0.5phr light (heat) stabilizer, 1phr dibasic lead phosphite, 2phr tribasic lead sulfate, 0.5phr stearic acid are added in the PVC resin (PVC-SG8 of Yibin Tianyuan Chemical Factory) of 100phr respectively, in Knead at about 170°C for about 8 minutes in a two-roller mixer, and then press at about 180°C to form the PVC material for testing.

The light (heat) stabilizer refers to 2-hydroxy-4-methoxyl-5-sulfonic acid benzophenone, hydrotalcite and the organic-inorganic composite light-heat stabilizer of the present invention respectively. 1# is the PVC sample that adds 0.5phr 2-hydroxyl-4-methoxy-5-sulfonic acid benzophenone; 2# is the PVC sample that adds 0.5phr hydrotalcite; 3# is that adds 0.5phr the present invention The PVC sample of the organic-inorganic composite photothermal stabilizer I. The test results are shown in Table 1 below.

Table1

Example 2:

1phr light (heat) stabilizer, 1phr dibasic lead phosphite, 2phr tribasic lead sulfate, 0.5phr stearic acid are added in the PVC resin (PVC-SG8 of Yibin Tianyuan chemical factory) of 100phr respectively, in double Knead in a roller mixer at about 170°C for about 10 minutes, and then press at about 180°C to form the required PVC material for testing.

The light (heat) stabilizer refers to 2-hydroxy-4-methoxyl-5-sulfonic acid benzophenone, hydrotalcite and the organic-inorganic composite light-heat stabilizer of the present invention respectively. 1# is the PVC sample that adds 1phr 2-hydroxyl-4-methoxy-5-sulfonic acid benzophenone; 2# is the PVC sample that adds 1phr hydrotalcite; 3# is the organic- PVC sample of inorganic composite photothermal stabilizer II. The test results are shown in Table 2 below.

Table 2

Example 3:

3phr light (heat) stabilizer, 1phr dibasic lead phosphite, 2phr tribasic lead sulfate, 0.5phr stearic acid are added in the pVC resin (PVC-SG8, Yibin Tianyuan chemical plant) of 100phr respectively, in double Knead in a roller mixer at about 170°C for about 10 minutes, and then press at about 180°C to form the required PVC material for testing.

The light (heat) stabilizer refers to 2-hydroxy-4-methoxyl-5-sulfonic acid benzophenone, hydrotalcite and the organic-inorganic composite light-heat stabilizer of the present invention respectively. 1# is the PVC sample that adds 3phr 2-hydroxyl-4-methoxyl group-5-sulfonic acid benzophenone; 2# is the PVC sample that adds 3phr hydrotalcite; 3# is the sample that adds 3phr present embodiment PVC sample of organic-inorganic composite photothermal stabilizer I. The test results are shown in Table 3 below.

Table3

^* Degraded rapidly, unable to prepare samples

Example 4:

5phr light (heat) stabilizer, 1phr dibasic lead phosphite, 2phr tribasic lead sulfate, 0.5phr stearic acid are added in the PVC resin (PVC-SG8 of Yibin Tianyuan Chemical Factory) of 100phr respectively, in double Knead in a roller mixer at about 170°C for about 10 minutes, and then press at about 180°C to form the required PVC material for testing.

The light (heat) stabilizer refers to 2-hydroxy-4-methoxyl-5-sulfonic acid benzophenone, hydrotalcite and the organic-inorganic composite light-heat stabilizer of the present invention respectively. 1# is the PVC sample that adds 5phr 2-hydroxyl-4-methoxy-5-sulfonic acid benzophenone; 2# is the PVC sample that adds 5phr hydrotalcite; 3# is the organic- PVC sample of inorganic composite photothermal stabilizer II. The test results are shown in Table 4 below.

Table 4

^* Degraded rapidly, unable to prepare samples

Example 5:

5phr light (heat) stabilizer, 1phr dibasic lead phosphite, 2phr tribasic lead sulfate, 0.5phr stearic acid are added in the PVC resin (PVC-SG8 of Yibin Tianyuan Chemical Factory) of 100phr respectively, in double Knead in a roller mixer at about 170°C for about 10 minutes, and then press at about 180°C to form the required PVC material for testing.

The light (heat) stabilizer refers to 2-hydroxy-4-methoxyl-5-sulfonic acid benzophenone, hydrotalcite and the organic-inorganic composite light-heat stabilizer of the present invention respectively. 1# is the PVC sample that adds 5phr 2-hydroxyl-4-methoxy-5-sulfonic acid benzophenone; 2# is the PVC sample that adds 5phr hydrotalcite; 3# is the organic- PVC sample of inorganic composite light and heat stabilizer III. The test results are shown in Table 5 below.

Table 5

^* Degraded rapidly, unable to prepare samples

Embodiment 6:

1phr light (heat) stabilizer, 1phr dibasic lead phosphite, 2phr tribasic lead sulfate, 0.5phr stearic acid are added in the PVC resin (PVC-SG8 of Yibin Tianyuan chemical factory) of 100phr respectively, in double Knead in a roller mixer at about 170°C for about 10 minutes, and then press at about 180°C to form the required PVC material for testing.

The light (heat) stabilizer refers to 2-hydroxy-4-methoxyl-5-sulfonic acid benzophenone, hydrotalcite and the organic-inorganic composite light-heat stabilizer of the present invention respectively. 1# is the PVC sample that adds 1 phr 2-hydroxyl-4-methoxy-5-sulfonic acid benzophenone; 2# is the PVC sample that adds 1 phr hydrotalcite; 3# is that adds 1 phr the present invention The PVC sample of the organic-inorganic composite photothermal stabilizer III. The test results are shown in Table 6 below.

Table 6

Claims (9)

1. organic-inorganic composite optothermal stabilizer, it is characterized in that the raw material composition mainly contains 2-hydroxyl-4-methoxyl group-5-sulfonic acid benzophenone, hydrotalcite, coupling agent and free radical scavenger, wherein the weight content ratio of hydrotalcite and 2-hydroxyl-4-methoxyl group-5-sulfonic acid benzophenone is 0.5～10, the weight content of coupling agent and free radical scavenger is respectively the 0.2%-5% and the 0.5%-10% of talcum and 2-hydroxyl-4-methoxyl group-5-sulfonic acid benzophenone gross weight, and described free radical scavenger is the compound that contains following structural unit:

R wherein ₁For containing 1,1,2,2, the group of-tetramethyl piperidine ring.

2. organic-inorganic composite optothermal stabilizer according to claim 1 is characterized in that described coupling agent is selected from titanate coupling agent and silane coupling agent.

3. organic-inorganic composite optothermal stabilizer according to claim 1 is characterized in that described hydrotalcite is the natural water talcum.

4. the method for preparing the described organic-inorganic composite optothermal stabilizer of one of claim 1 to 3 is characterized in that mainly may further comprise the steps:

(1) will determine the 2-hydroxyl-4-methoxyl group-5-sulfonic acid benzophenone of proportional and insert reactor through the hydrotalcite that calcination process is crossed and add entry and be mixed with the aqueous solution, carry out anion exchange reaction in 50～100 ℃, fully reaction is after separation, washing, drying make organic-inorganic composition;

(2) behind organic-inorganic composition that step (1) is made and the true quantitative coupling agent thorough mixing, place water or ethanol, add true quantitative free radical scavenger, apply ultrasonic irradiation, mixture and free radical scavenger are fully interacted, after filtration, washing, drying treatment make organic-inorganic composite optothermal stabilizer.

5. organic-inorganic composite optothermal stabilizer preparation method according to claim 4 is characterized in that described hydrotalcite calcination process is in 300-800 ℃ of roasting 1-10 hour.

6. organic-inorganic composite optothermal stabilizer preparation method according to claim 4 is characterized in that described ultrasonic irradiation is by material 5-250kW/m ³Shone 10-30 minute.

7. organic-inorganic composite optothermal stabilizer preparation method according to claim 6 is characterized in that described frequency of ultrasonic is 20kHz.

8. organic-inorganic composite optothermal stabilizer preparation method according to claim 4 is characterized in that described anion exchange reaction reacted 10～50 hours down in 50～100 ℃.

9. by the polyvinyl chloride of the described organic-inorganic composite optothermal stabilizer preparation of one of claim 1 to 3, it is characterized in that main ingredient constitutes, and counts with weight part:

Polyvinyl chloride resin 100

Organic-inorganic composite optothermal stabilizer 0.5-5

Dibasic lead phosphite 1-3

Lead sulfate tribasic 1-3

Stearic acid 0.3-1.