PVC foam and preparation method thereof
By using specific raw materials and process treatment in PVC foam, PVC foam with excellent mechanical properties and improved thermal stability is formed, which solves the problems of poor thermal stability and poor mechanical properties of existing PVC foams.
Patent Information
- Application Number
- CN202510145754.4
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-02-10
- Publication Date
- 2025-04-08
AI Technical Summary
The existing PVC foam has poor thermal stability and poor mechanical properties under heated conditions, resulting in a short life and is difficult to meet the needs of widespread applications.
The polyvinyl chloride resin was stirred and mixed with raw materials such as tributyl trans aconitate, potassium azoformamide formate, hexamethylene diisocyanate, 3,4-epoxycyclohexylmethyl 3,4-epoxycyclohexyl cyclohexyl 4,5-epoxytetrahydrophthalate, modified mullite whiskers, polycarbosilane and dinolyl dianiline to form a paste material, and PVC foam was prepared by molding and further foaming.
The prepared PVC foam has excellent mechanical properties, including high tensile strength and impact resistance, and has significantly improved thermal stability, extending its service life.
Smart Images
Figure SMS_1
Abstract
Description
Technical Field
[0001] The invention belongs to the technical field of PVC foam preparation, and specifically relates to PVC foam and a preparation method thereof. Background Art
[0002] PVC is one of the five major general-purpose resins in the world. At present, my country's PVC industry ranks first in the world in terms of production capacity, output and consumption. PVC products have the advantages of good mechanical properties and low cost, so they are widely used in the fields of chemical industry, pipes and packaging. The chlorine atoms in the PVC structure are very active, which makes it easy for PVC to release HCl under heating conditions, that is, the thermal stability is poor. When PVC releases a large amount of HCl, its mechanical properties will drop significantly, resulting in a short service life during service. How to modify PVC to improve its thermal stability and mechanical properties has become the main direction of the development of the PVC industry.
[0003] There are two main methods to enhance the plasticity of PVC: blending modification and chemical modification. Blending modification is physical mixing, that is, mixing plasticizers with PVC to improve the plasticity of PVC; chemical modification is to change the molecular structure of PVC through corresponding chemical reactions, so as to achieve the purpose of internal plasticization. Chemical modification methods are mainly divided into grafting modification, copolymerization modification, cross-linking reaction modification, etc. There are many chemical cross-linking methods, mainly including peroxide cross-linking, triazine compound cross-linking, diene compound cross-linking, silane cross-linking, etc. The cross-linking modifier "sticks" two PVC chains together like an adhesive. The "stickiness" of the cross-linking agent and the cross-linking method have a fundamental impact on the stability of the modified PVC. At the same time, the selectivity of the PVC chain to the cross-linking agent, that is, the substitution rate of the cross-linking agent on the PVC chain, puts forward higher requirements on the cross-linking agent of the modified PVC.
[0004] Therefore, exploring a suitable modification method to improve the mechanical properties of PVC foam and expand the application areas of PVC foam has become a technical problem that needs to be solved urgently. Summary of the invention
[0005] The purpose of the present invention is to provide a PVC foam, wherein the prepared PVC foam has excellent mechanical properties; the present invention also provides a preparation method thereof.
[0006] The PVC foam of the present invention is composed of the following raw materials in parts by weight: 100 parts of polyvinyl chloride resin, 3-3.5 parts of trans-tributyl aconitate, 5.5-6 parts of potassium azodicarbonamide formate, 60-65 parts of hexamethylene diisocyanate, 23-25 parts of 3,4-epoxycyclohexylmethyl 3,4-epoxycyclohexylcarboxylate, 2-4 parts of 4,5-epoxytetrahydrophthalic acid dioctyl ester, 8.7-9.3 parts of modified mullite whisker, 4.0-5.5 parts of polycarbosilane and 6.2-6.7 parts of dinonyldiphenylamine.
[0007] in: The preparation method of the modified mullite whisker comprises the following steps: 1. mixing 3-aminopropyltriethoxysilane with deionized water, then adding acetic acid to adjust the pH value of the solution to 4, and hydrolyzing it at room temperature and pressure for 2.5 hours to prepare a modifier solution; 2. dissolving the mullite whisker in ethanol to prepare a suspension; 3. magnetically stirring the suspension prepared in step 2, then dripping the modifier solution, reacting at 60-63°C for 75-80 minutes, and finally filtering, washing, and drying to prepare the modified mullite whisker.
[0008] in: In step ①, the mass ratio of 3-aminopropyltriethoxysilane to deionized water is 1.5:1.
[0009] In step ②, the mass volume ratio of mullite whiskers to ethanol is 1:20, in g / mL.
[0010] The mass of 3-aminopropyltriethoxysilane accounts for 3.5% of the mass of the mullite whiskers.
[0011] In step ③, the magnetic stirring speed is 350 r / min, and the magnetic stirring time is 0.7 h.
[0012] In step ③, the drying temperature is 80-85°C and the drying time is 6.5h.
[0013] The PVC foam of the present invention uses polyvinyl chloride resin as the main raw material and trans-tributyl aconitate as the plasticizer. As a bio-based plasticizer, it can improve the toughness of PVC foam and the impact resistance of PVC foam. Potassium azodicarbonamide formate is used as the foaming agent, which decomposes under heat to produce gases such as N2, CO and CO2. -COOK in its structure can neutralize HCl generated during PVC processing to prevent HCl from catalyzing the degradation of PVC. Therefore, potassium azodicarbonamide formate has the dual functions of foaming and stabilization. Hexamethylene diisocyanate, 3,4-epoxycyclohexylmethyl 3,4-epoxycyclohexylcarboxylate and 4,5-epoxytetrahydrophthalic acid dioctyl ester are used as crosslinking grafting modifiers, wherein 3,4-epoxycyclohexylmethyl 3,4-epoxycyclohexylcarboxylate contains two active epoxy groups, each of which can react with an isocyanate group, thereby forming multiple crosslinking points on the PVC molecular chain. In addition, its addition can improve the processability of PVC, and compounding with 4,5-epoxytetrahydrophthalic acid dioctyl ester can improve the stability of PVC products. Thus, by forming multiple crosslinking points between PVC molecular chains to form a three-dimensional crosslinking network, the formation of a three-dimensional crosslinking network can make the prepared PVC foam have excellent tensile strength and impact resistance, and the interaction between PVC molecular chains is enhanced, so that stress can be better dispersed when subjected to external forces.
[0014] In addition, modified mullite whisker, polycarbosilane and dinonyldiphenylamine are creatively added to the PVC foam described in the present application, and the three act synergistically to further improve the mechanical properties of the PVC foam. After the mullite whisker is modified by KH-550 silane coupling agent, it has excellent dispersibility and its addition can improve the microstructure of the PVC foam, make the pores more uniform and dense, and improve the closed cell rate, and the uniform pore structure helps to disperse stress, reduce stress concentration, thereby further improving the mechanical properties of the PVC foam. The benzene ring structure in dinonyldiphenylamine forms a weak intermolecular force with the chlorine atom in the PVC molecular chain, strengthens the intermolecular bonding force, thereby improving the mechanical properties of PVC. The silicon-oxygen bond and the carbon-silicon bond in the polycarbosilane can interact with the PVC molecular chain, thereby strengthening the interfacial bonding force, and then improving the comprehensive performance of the prepared PVC. Thus, the three interact with each other, and the mechanical properties of the prepared PVC foam are further improved on the basis of the cross-linked polyvinyl chloride prepared.
[0015] The preparation method of PVC foam of the present invention comprises the following steps: (1) polyvinyl chloride resin, tributyl trans-aconitate, potassium azodicarbonamide formate, hexamethylene diisocyanate, 3,4-epoxycyclohexylmethyl 3,4-epoxycyclohexylcarboxylate, dioctyl 4,5-epoxytetrahydrophthalate, modified mullite whisker, polycarbosilane and dinonyldiphenylamine are stirred and mixed uniformly to prepare a paste material; (2) pouring the paste into a mold for molding, and then opening the mold after cooling to prepare a pre-foamed body; (3) The pre-foamed body is placed in water at 95-97°C for further foaming, and then cured to prepare PVC foam.
[0016] in: In step (2), the molding temperature is 178-180°C and the molding pressure is 17 MPa.
[0017] In step (3), the curing temperature is 63-65°C and the curing time is 82h.
[0018] Compared with the prior art, it has the following beneficial effects: (1) The PVC foam described in the present invention first undergoes cross-linking and grafting modification treatment on polyvinyl chloride using hexamethylene diisocyanate, 3,4-epoxycyclohexylmethyl 3,4-epoxycyclohexylcarboxylate and 4,5-epoxytetrahydrophthalate to form a three-dimensional network structure, thereby ensuring that the PVC foam has a certain mechanical strength; and then further improves the mechanical strength of the prepared PVC foam by adding a mixture of modified mullite whiskers, polycarbosilane and dinonyldiphenylamine.
[0019] (2) The preparation method of the PVC foam of the present invention has a simple process and easy-to-control parameters, and the prepared PVC foam has stable and excellent performance. DETAILED DESCRIPTION
[0020] The present invention is further described below with reference to the embodiments.
[0021] Example 1 The PVC foam described in Example 1 is composed of the following raw materials, in parts by weight: 100 parts of polyvinyl chloride resin, 3.3 parts of tributyl trans-aconitate, 5.7 parts of potassium azodicarbonamide formate, 63 parts of hexamethylene diisocyanate, 24 parts of 3,4-epoxycyclohexylmethyl 3,4-epoxycyclohexylcarboxylate, 3 parts of dioctyl 4,5-epoxytetrahydrophthalate, 9.0 parts of modified mullite whiskers, 4.7 parts of polycarbosilane, and 6.5 parts of dinonyldiphenylamine.
[0022] in: The preparation method of the modified mullite whisker comprises the following steps: 1. mixing 3-aminopropyltriethoxysilane with deionized water, then adding acetic acid to adjust the pH value of the solution to 4, and hydrolyzing it at room temperature and pressure for 2.5 hours to prepare a modifier solution; 2. dissolving the mullite whisker in ethanol to prepare a suspension; 3. magnetically stirring the suspension prepared in step 2, then dripping the modifier solution, reacting at 61°C for 78 minutes, and finally filtering, washing, and drying to prepare the modified mullite whisker.
[0023] in: In step ①, the mass ratio of 3-aminopropyltriethoxysilane to deionized water is 1.5:1.
[0024] In step ②, the mass volume ratio of mullite whiskers to ethanol is 1:20, in g / mL.
[0025] The mass of 3-aminopropyltriethoxysilane accounts for 3.5% of the mass of the mullite whiskers.
[0026] In step ③, the magnetic stirring speed is 350 r / min, and the magnetic stirring time is 0.7 h.
[0027] In step ③, the drying temperature is 83°C and the drying time is 6.5h.
[0028] The method for preparing the PVC foam described in this embodiment 1 comprises the following steps: (1) polyvinyl chloride resin, tributyl trans-aconitate, potassium azodicarbonamide formate, hexamethylene diisocyanate, 3,4-epoxycyclohexylmethyl 3,4-epoxycyclohexylcarboxylate, dioctyl 4,5-epoxytetrahydrophthalate, modified mullite whisker, polycarbosilane and dinonyldiphenylamine are stirred and mixed uniformly to prepare a paste material; (2) pouring the paste into a mold for molding, and then opening the mold after cooling to prepare a pre-foamed body; (3) The pre-foamed body is placed in water at 96° C. for further foaming, and then cured to prepare PVC foam.
[0029] in: In step (2), the molding temperature is 179° C. and the molding pressure is 17 MPa.
[0030] In step (3), the curing temperature is 64° C. and the curing time is 82 h.
[0031] Example 2 The PVC foam described in this embodiment 2 is composed of the following raw materials, measured in parts by weight: 100 parts of polyvinyl chloride resin, 3 parts of tributyl trans-aconitate, 5.5 parts of potassium azodicarbonamide formate, 60 parts of hexamethylene diisocyanate, 25 parts of 3,4-epoxycyclohexylmethyl 3,4-epoxycyclohexylcarboxylate, 2 parts of dioctyl 4,5-epoxytetrahydrophthalate, 8.7 parts of modified mullite whiskers, 5.5 parts of polycarbosilane, and 6.2 parts of dinonyldiphenylamine.
[0032] in: The preparation method of the modified mullite whisker comprises the following steps: 1. mixing 3-aminopropyltriethoxysilane with deionized water, then adding acetic acid to adjust the pH value of the solution to 4, and hydrolyzing it at room temperature and pressure for 2.5 hours to prepare a modifier solution; 2. dissolving the mullite whisker in ethanol to prepare a suspension; 3. magnetically stirring the suspension prepared in step 2, then dripping the modifier solution, reacting at 60°C for 80 minutes, and finally filtering, washing, and drying to prepare the modified mullite whisker.
[0033] in: In step ①, the mass ratio of 3-aminopropyltriethoxysilane to deionized water is 1.5:1.
[0034] In step ②, the mass volume ratio of mullite whiskers to ethanol is 1:20, in g / mL.
[0035] The mass of 3-aminopropyltriethoxysilane accounts for 3.5% of the mass of the mullite whiskers.
[0036] In step ③, the magnetic stirring speed is 350 r / min, and the magnetic stirring time is 0.7 h.
[0037] In step ③, the drying temperature is 80°C and the drying time is 6.5h.
[0038] The method for preparing the PVC foam described in this embodiment 2 comprises the following steps: (1) polyvinyl chloride resin, tributyl trans-aconitate, potassium azodicarbonamide formate, hexamethylene diisocyanate, 3,4-epoxycyclohexylmethyl 3,4-epoxycyclohexylcarboxylate, dioctyl 4,5-epoxytetrahydrophthalate, modified mullite whisker, polycarbosilane and dinonyldiphenylamine are stirred and mixed uniformly to prepare a paste material; (2) pouring the paste into a mold for molding, and then opening the mold after cooling to prepare a pre-foamed body; (3) The pre-foamed body is placed in water at 95° C. for further foaming, and then cured to prepare PVC foam.
[0039] in: In step (2), the molding temperature is 178° C. and the molding pressure is 17 MPa.
[0040] In step (3), the curing temperature is 63° C. and the curing time is 82 h.
[0041] Example 3 The PVC foam described in this embodiment 3 is composed of the following raw materials, measured in parts by weight: 100 parts of polyvinyl chloride resin, 3.5 parts of tributyl trans-aconitate, 6 parts of potassium azodicarbonamide formate, 65 parts of hexamethylene diisocyanate, 23 parts of 3,4-epoxycyclohexylmethyl 3,4-epoxycyclohexylcarboxylate, 4 parts of 4,5-epoxytetrahydrophthalic acid dioctyl ester, 9.3 parts of modified mullite whiskers, 4.0 parts of polycarbosilane, and 6.7 parts of dinonyldiphenylamine.
[0042] in: The preparation method of the modified mullite whisker comprises the following steps: 1. mixing 3-aminopropyltriethoxysilane with deionized water, then adding acetic acid to adjust the pH value of the solution to 4, and hydrolyzing it at room temperature and pressure for 2.5 hours to prepare a modifier solution; 2. dissolving the mullite whisker in ethanol to prepare a suspension; 3. magnetically stirring the suspension prepared in step 2, then dripping the modifier solution, reacting at 63°C for 75 minutes, and finally filtering, washing, and drying to prepare the modified mullite whisker.
[0043] in: In step ①, the mass ratio of 3-aminopropyltriethoxysilane to deionized water is 1.5:1.
[0044] In step ②, the mass volume ratio of mullite whiskers to ethanol is 1:20, in g / mL.
[0045] The mass of 3-aminopropyltriethoxysilane accounts for 3.5% of the mass of the mullite whiskers.
[0046] In step ③, the magnetic stirring speed is 350 r / min, and the magnetic stirring time is 0.7 h.
[0047] In step ③, the drying temperature is 85°C and the drying time is 6.5h.
[0048] The method for preparing the PVC foam described in this embodiment 3 comprises the following steps: (1) polyvinyl chloride resin, tributyl trans-aconitate, potassium azodicarbonamide formate, hexamethylene diisocyanate, 3,4-epoxycyclohexylmethyl 3,4-epoxycyclohexylcarboxylate, dioctyl 4,5-epoxytetrahydrophthalate, modified mullite whisker, polycarbosilane and dinonyldiphenylamine are stirred and mixed uniformly to prepare a paste material; (2) pouring the paste into a mold for molding, and then opening the mold after cooling to prepare a pre-foamed body; (3) The pre-foamed body is placed in water at 97° C. for further foaming, and then cured to prepare PVC foam.
[0049] in: In step (2), the molding temperature is 180° C. and the molding pressure is 17 MPa.
[0050] In step (3), the curing temperature is 65° C. and the curing time is 82 h.
[0051] Comparative Example 1 The preparation method of the PVC foam described in this comparative example 1 is the same as that of Example 1, and the only difference is that the raw material composition is different. The PVC foam described in this comparative example 1 is composed of the following raw materials in parts by weight: 100 parts of polyvinyl chloride resin, 3.3 parts of trans-tributyl aconitate, 5.7 parts of potassium azodicarbonamide formate, 63 parts of hexamethylene diisocyanate, 24 parts of 3,4-epoxycyclohexylmethyl 3,4-epoxycyclohexylcarboxylate, 3 parts of 4,5-epoxytetrahydrophthalic acid dioctyl ester, 4.7 parts of polycarbosilane, and 6.5 parts of dinonyl diphenylamine.
[0052] Comparative Example 2 The preparation method of the PVC foam described in this comparative example 2 is the same as that of Example 1, and the only difference is that the raw material composition is different. The PVC foam described in this comparative example 2 is composed of the following raw materials in parts by weight: 100 parts of polyvinyl chloride resin, 3.3 parts of trans-tributyl aconitate, 5.7 parts of potassium azodicarbonamide formate, 63 parts of hexamethylene diisocyanate, 24 parts of 3,4-epoxycyclohexylmethyl 3,4-epoxycyclohexylcarboxylate, 3 parts of 4,5-epoxytetrahydrophthalic acid dioctyl ester, 9.0 parts of modified mullite whiskers, and 6.5 parts of dinonyl diphenylamine.
[0053] Comparative Example 3 The preparation method of the PVC foam described in this comparative example 3 is the same as that of Example 1, and the only difference is that the raw material composition is different. The PVC foam described in this comparative example 3 is composed of the following raw materials in parts by weight: 100 parts of polyvinyl chloride resin, 3.3 parts of trans-tributyl aconitate, 5.7 parts of potassium azodicarbonamide formate, 63 parts of hexamethylene diisocyanate, 24 parts of 3,4-epoxycyclohexylmethyl 3,4-epoxycyclohexylcarboxylate, 3 parts of 4,5-epoxytetrahydrophthalic acid dioctyl ester, 9.0 parts of modified mullite whiskers, and 4.7 parts of polycarbosilane.
[0054] The performance tests were performed on the PVC foams prepared in Examples 1-3 and Comparative Examples 1-3. The results are shown in Table 1 below: Table 1 PVC foam performance test results
Claims
1. A PVC foam, characterized in that: The invention is composed of the following raw materials in parts by weight: 100 parts of polyvinyl chloride resin, 3-3.5 parts of trans-tributyl aconitate, 5.5-6 parts of potassium azodicarbonamide formate, 60-65 parts of hexamethylene diisocyanate, 23-25 parts of 3,4-epoxycyclohexylmethyl 3,4-epoxycyclohexylcarboxylate, 2-4 parts of 4,5-epoxytetrahydrophthalic acid dioctyl ester, 8.7-9.3 parts of modified mullite whisker, 4.0-5.5 parts of polycarbosilane and 6.2-6.7 parts of dinonyldiphenylamine.
2. The PVC foam according to claim 1, characterized in that: The preparation method of the modified mullite whisker comprises the following steps:
1. mixing 3-aminopropyltriethoxysilane with deionized water, then adding acetic acid to adjust the pH value of the solution to 4, and hydrolyzing it at room temperature and pressure for 2.5 hours to prepare a modifier solution; 2. dissolving the mullite whisker in ethanol to prepare a suspension; 3. magnetically stirring the suspension prepared in step 2, then dripping the modifier solution, reacting at 60-63°C for 75-80 minutes, and finally filtering, washing, and drying to prepare the modified mullite whisker.
3. The PVC foam according to claim 2, characterized in that: In step ①, the mass ratio of 3-aminopropyltriethoxysilane to deionized water is 1.5:
1.
4. The PVC foam according to claim 2, characterized in that: In step ②, the mass volume ratio of mullite whiskers to ethanol is 1:20, in g / mL.
5. The PVC foam according to claim 2, characterized in that: The mass of 3-aminopropyltriethoxysilane accounts for 3.5% of the mass of the mullite whiskers.
6. The PVC foam according to claim 2, characterized in that: In step ③, the magnetic stirring speed is 350 r / min, and the magnetic stirring time is 0.7 h.
7. The PVC foam according to claim 2, characterized in that: In step ③, the drying temperature is 80-85°C and the drying time is 6.5h.
8. A method for preparing the PVC foam according to claim 1, characterized in that: It consists of the following steps: (1) polyvinyl chloride resin, tributyl trans-aconitate, potassium azodicarbonamide formate, hexamethylene diisocyanate, 3,4-epoxycyclohexylmethyl 3,4-epoxycyclohexylcarboxylate, dioctyl 4,5-epoxytetrahydrophthalate, modified mullite whisker, polycarbosilane and dinonyldiphenylamine are stirred and mixed uniformly to prepare a paste material; (2) pouring the paste into a mold for molding, and then opening the mold after cooling to prepare a pre-foamed body; (3) The pre-foamed body is placed in water at 95-97° C. for further foaming, and then cured to prepare PVC foam.
9. The method for preparing PVC foam according to claim 8, characterized in that: In step (2), the molding temperature is 178-180°C and the molding pressure is 17 MPa.
10. The method for preparing PVC foam according to claim 8, characterized in that: In step (3), the curing temperature is 63-65°C and the curing time is 82h.