Chlorinated polyvinyl chloride grafted cross-linked foam material and preparation method thereof
By generating CPVC material carrying active groups under the action of a catalyst and reacting it with grafted material to form a cross-network structure, the problem of performance degradation caused by excessive additives in the CPVC foaming process is solved, achieving comprehensive improvement in material performance and cost optimization.
Patent Information
- Application Number
- CN202511959654.1
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-12-24
- Publication Date
- 2026-03-20
AI Technical Summary
Existing CPVC foaming technology suffers from problems such as uneven cell structure, insufficient mechanical strength, poor dimensional stability, and low heat distortion temperature. Furthermore, the addition of a large amount of additives leads to a decline in performance.
By adding active group additives under the action of a catalyst to react with CPVC to generate CPVC material carrying active groups, and then reacting with grafted materials to form a cross-linked network structure, the dependence on additives is reduced and cross-linked foaming is achieved.
It improves the stiffness and strength of foam materials, enhances tensile strength, tensile modulus, compressive strength, shear strength and heat distortion temperature, has a uniform cell structure, excellent mechanical properties, good dimensional stability, and reduces production costs.
Smart Images
Figure CN121699320A_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The application belongs to the technical field of chlorinated polyvinyl chloride foaming materials, and particularly relates to a chlorinated polyvinyl chloride graft crosslinking foaming material and a preparation method thereof. BACKGROUND
[0002] Chlorinated polyvinyl chloride (CPVC) is a material obtained by chlorinating PVC, and the chlorine content is between 60-72%. The increase of the chlorine content endows CPVC with a series of excellent properties. CPVC has excellent heat resistance, corrosion resistance and flame resistance, high heat distortion temperature, good heat resistance, strong affinity and is easy to print, and is an ideal substrate for high-strength hard materials and is widely used. However, CPVC has large viscosity, obvious processing heat generation, poor processing thermal stability, easy yellowing, strong material polarity and large viscosity, and therefore requires the addition of processing aids, stabilizers, lubricants and the like. Such formulation design reduces the inherent properties of CPVC as a high-strength hard material. After foaming, CPVC can achieve good strength, lightness and poor deformation, and has the effects of sound insulation, heat insulation, heat preservation, flame resistance, moisture resistance and mildew resistance, thereby realizing the expansion of the application range of light weight and having wide application prospects in the fields of wind power structure foaming materials, roofs of locomotives, interior decoration plates, outer wall plates of buildings, interior decoration plates, cold storage and special cold preservation engineering plates and environment-friendly templates.
[0003] In the prior art, the non-crosslinking CPVC foaming technology is mainly focused on the direct application of physical or chemical foaming agents, and problems such as uneven cell structure, insufficient mechanical strength, poor dimensional stability and low heat distortion temperature are prone to occur, and it is difficult to achieve both performance. This is because CPVC itself has high strength but poor stability and processing difficulty, and some properties are also short boards (impact strength), and various additives need to be added to improve the performance, but this weakens the support strength of the cell and causes the performance of the material to decrease. The crosslinking method for improving the performance mainly adds a large amount of initiation and reaction aids to improve the ability to form a network structure in the processing process, mainly because the reaction activity of CPVC molecules is not enough and the precision is insufficient, and a large amount of additives need to be added to increase the crosslinking opportunity, but the addition of a large amount of additives will obviously affect the strength of the product, and the crosslinking material itself can form a polymer, and when a large amount of additives are added, the product is actually a co-foaming product of CPVC and the crosslinking material, which crosslinks CPVC while reducing the performance strength of CPVC. SUMMARY
[0004] In view of the deficiencies in the prior art, the present application provides a chlorinated polyvinyl chloride grafted crosslinked foaming material and a preparation method thereof, wherein under the action of a catalyst, an active group additive is added to react with CPVC to generate CPVC material carrying an active group, then the CPVC carrying the active group reacts with a grafted material to generate grafted CPVC, and finally a cross network structure is formed by the reaction of a reactive additive and a grafting group in the foaming process, thereby solving the problem of the decline in overall performance caused by the large amount of additives added to maintain the crosslinking degree in the CPVC crosslinking foaming process.
[0005] To solve the above technical problems, the technical scheme of the present application is: The chlorinated polyvinyl chloride grafted crosslinked foaming material is composed of the following raw materials by weight: chlorinated polyvinyl chloride 95-105 parts, trimethylsilane azide 1-3 parts, organotin catalyst 0.5-2 parts, grafting reaction additive 2-4 parts, crosslinking additive 4.5-7.5 parts, composite foaming agent 2-10 parts, stabilizer 4-7 parts, impact modifier 1.5-3 parts, processing additive 1-2.5 parts, lubricant 1-2.5 parts, and filling material 3-5.5 parts.
[0006] Preferably, the chlorine content of the chlorinated polyvinyl chloride is in the range of 60-65%, and the melt viscosity is 1600-1800 Pa.s.
[0007] Preferably, the organotin catalyst is one of dibutyltin dilaurate and bis(dodecylthio) dibutyltin.
[0008] Preferably, the grafting reaction additive is one of hexamethylene diamine and tetramethylmethane diamine.
[0009] Preferably, the crosslinking additive is one of octadecane diacid, tetradecane diacid, and dodecane dicarboxylic acid.
[0010] Preferably, the composite foaming agent is composed of a main foaming agent, an auxiliary foaming agent, and a foaming additive in a mass ratio of 1-5:0.8-4.5:1.4-2.5; the main foaming agent is azodicarbonamide; the auxiliary foaming agent is sodium bicarbonate; the foaming additive is composed of zinc oxide, zinc stearate, stearic acid, palmitic acid, and a foaming regulator in a mass ratio of 0.2-0.4:0.4-0.8:0-0.8:0-1:0.3-0.5; and the foaming regulator preferably uses an acrylate foaming regulator, such as HF-90, with a molecular weight of 2000000-2500000.
[0011] Preferably, the stabilizer includes a main stabilizer and an auxiliary stabilizer, the main stabilizer is one of methyl mercaptan tin, butyl mercaptan tin, butyl tin laurate, and butyl tin maleate, and the auxiliary stabilizer is one or a combination of more than two of antioxidant 1010, epoxy soybean oil, and hydrotalcite in any proportion.
[0012] Preferably, the impact modifier is one or a combination of acrylate impact modifier, methyl methacrylate-butadiene-styrene copolymer in any proportion.
[0013] Preferably, the processing aid is one of oxidized polyethylene wax or acrylate processing aid, such as K125P, ACR401, ACR201, K175P, P251.
[0014] Preferably, the lubricant is one or a combination of paraffin wax, polyethylene wax, fatty acid complex alcohol ester, chlorinated paraffin wax, Fischer-Tropsch wax in any proportion; the filler is one or a combination of titanium dioxide, nano calcium carbonate in any proportion.
[0015] The preparation method of the chlorinated polyvinyl chloride grafted cross-linked foaming material, comprising the following steps: S1, the mass fraction of each raw material is determined, the chlorinated polyvinyl chloride resin is put into a closed mixer, and the mixer is started to stir; trimethylsilane azide and organic tin catalyst are pre-mixed and slowly added to the chlorinated polyvinyl chloride resin in the mixer, the stirring speed of the mixer is controlled at 300-450 rpm, the material is gradually heated and stabilized at 60-75℃, under this condition, the stirring reaction is continued for 2-2.5 hours, the trimethylsilane azide reacts with the molecular chain of chlorinated polyvinyl chloride to realize the activation of the resin; S2, after the activation reaction, the stirring speed is reduced to 200-300 rpm, the material temperature is cooled to below 40℃, the grafting reaction aid is added to the mixer, the grafting reaction aid reacts with the activated chlorinated polyvinyl chloride, the stirring is carried out for 1-2 hours to complete the grafting modification, and the chlorinated polyvinyl amine grafting modified product is obtained; In this way, by pre-chemical activation and grafting modification of CPVC resin, reactive active sites are introduced on the molecular chain, which lays a foundation for subsequent cross-linking reaction, and the process uses specific types and amounts of silane azide compounds and organic tin catalysts to generate CPVC carrying active groups, then the material realizes CPVC grafting with grafting reaction aid (diamine grafting material) under mild conditions; S3, the chlorinated polyvinyl amine grafting modified product is added with stabilizer, lubricant, impact modifier, processing aid, filler in sequence, the stirring is carried out at a speed of 600-750 rpm, the temperature is raised to 115-120℃, the cross-linking aid is added after ensuring uniform dispersion, the stirring is carried out until the temperature reaches 125-130℃, then the material is immediately put into a cooling mixer for rapid cooling, the composite foaming agent is added, and the stirring and mixing are continued until the material temperature is lower than 40℃, forming the mixed material to be foamed; the mixed material is discharged from the cooling mixer and cooled for standby; S4. Set the processing temperature to 170-188℃. The foaming agent azodicarbonamide and sodium bicarbonate decompose to generate gas under the action of a catalyst. At the same time, the crosslinking aid (specific long-chain dicarboxylic acid) undergoes a condensation reaction with the chlorinated polyvinyl chloride amine graft modification product to achieve directional crosslinking and form crosslinking bonds. These two processes occur simultaneously. The gas causes the material to expand and form a cell structure, while the condensation crosslinking reaction forms a stable network structure between molecules, stabilizing the cells. After foaming, molding and cooling, the final chlorinated polyvinyl chloride graft crosslinked foam material product can be obtained.
[0016] This built-in crosslinking mechanism can significantly reduce reliance on traditional plasticizers, modifiers, and other functional additives, thereby reducing the negative impacts of these additives and achieving significant improvements in key properties such as compressive strength, tensile strength, shear strength, modulus, and heat distortion temperature.
[0017] Compared with the prior art, the present invention has the following beneficial effects: (1) The chlorinated polyvinyl chloride graft crosslinking foaming material provided by the present invention, under the action of a catalyst, reacts with CPVC by adding the active group additive trimethylsilazine to generate CPVC material carrying active groups. The active group trimethylsilazine greatly enhances the grafting reaction activity of CPVC. Then, the CPVC carrying active groups reacts with diamine grafting materials to form CPVC graft copolymer. Grafting reduces the viscosity of CPVC, improves processing fluidity, and reduces the amount of processing aids and lubrication systems added in the later formulation, thereby reducing the negative impact on the strength performance of the product. Finally, during the foaming process, the reactive additives and grafting groups form a cross-network structure, and the reaction is highly targeted. The performance is enhanced through the grafting and crosslinking reaction of CPVC itself, reducing the dependence on the amount of additives. The amount of reactive additives added is greatly reduced, which not only reduces the raw material cost, but also reduces the impact on the environment. It solves the problem of overall performance decline caused by adding a large amount of additives to maintain the degree of crosslinking during the CPVC crosslinking foaming process.
[0018] (2) The chlorinated polyvinyl chloride graft crosslinking foaming material provided by the application has the following advantages: compared with a non-crosslinking formula design, the crosslinking structure enhances the interaction force between molecular chains, effectively limits the slippage of the molecular chains, so that the foaming material exhibits higher rigidity and strength when bearing external force, the tensile strength, tensile modulus, compressive strength, compressive modulus and shear modulus are obviously improved, the improvement ratio reaches 20-30%, the performance improvement also significantly improves the heat deformation resistance temperature of the material, so that the foaming material can still maintain shape stability in a higher temperature environment, the heat deformation resistance temperature of the CPVC foaming material after graft crosslinking is obviously improved, the improvement amplitude is 4-6 ℃. Meanwhile, the shear strain performance is also improved, which indicates that the product has high strength and good stiffness after graft crosslinking, meaning that the material has better toughness or deformation recovery capacity, which is crucial for the reliability of the foaming material in bearing or buffering applications.
[0019] (3) The chlorinated polyvinyl chloride graft crosslinking foaming material provided by the application has the following advantages: compared with a non-crosslinking formula design, the crosslinking structure enhances the interaction force between molecular chains, effectively limits the slippage of the molecular chains, so that the foaming material exhibits higher rigidity and strength when bearing external force, the tensile strength, tensile modulus, compressive strength, compressive modulus and shear modulus are obviously improved, the improvement ratio reaches 20-30%, the performance improvement also significantly improves the heat deformation resistance temperature of the material, so that the foaming material can still maintain shape stability in a higher temperature environment, the heat deformation resistance temperature of the CPVC foaming material after graft crosslinking is obviously improved, the improvement amplitude is 4-6 ℃. Meanwhile, the shear strain performance is also improved, which indicates that the product has high strength and good stiffness after graft crosslinking, meaning that the material has better toughness or deformation recovery capacity, which is crucial for the reliability of the foaming material in bearing or buffering applications. BRIEF DESCRIPTION OF DRAWINGS
[0020] The following drawings are only intended to schematically illustrate and explain the present application, and do not limit the scope of the present application. Among them: Figure 1 is the infrared spectrum of the CPVC material carrying active groups in Example 1; Figure 2 is the infrared spectrum of the chlorinated polyvinyl chloride amine grafting modified product in Example 1; Figure 3 is the electron microscope graph of the chlorinated polyvinyl chloride graft crosslinking foaming material product prepared in Example 1; Figure 4 is the electron microscope graph of the chlorinated polyvinyl chloride foaming material product prepared in Comparative Example 1. DETAILED DESCRIPTION
[0021] The present application will be further specifically described below in combination with examples and comparative examples. In the following detailed description, certain exemplary embodiments of the present application are described by way of illustration only. It is self-evident that those skilled in the art can modify the described embodiments in various ways without departing from the spirit and scope of the present application. Therefore, the description in the examples is illustrative in nature and is not intended to limit the protection scope of the claims.
[0022] The foaming materials in Examples 1-3 and Comparative Examples 1-3 include the raw material components shown in Table 1 in parts by weight. Among them, Examples 1, 2 and 3 differ in that the foaming ratio (density) of the material is controlled by designing different formulations.
[0023] Table 1 Example 1 S1, the raw material components are weighed according to the formulation; S2, the chlorinated polyvinyl chloride resin is put into a sealed high-speed mixer, and the mixer is started to stir; the weighed trimethylsilazide and the selected catalyst are pre-mixed, and slowly added to the chlorinated polyvinyl chloride resin in the mixer; the stirring speed of the mixer is controlled at 300 rpm, the material is gradually heated and stabilized at 60℃, under this condition, the stirring reaction is continued for 2.5 hours, so that the trimethylsilazide reacts with the molecular chain of chlorinated polyvinyl chloride to realize the activation of the resin; Figure 1 The infrared spectrum of the CPVC material carrying active groups is shown in the figure, and the absorption peak marked in the figure is the absorption peak of the azide group. There is no silicon-nitrogen absorption peak in the spectrum of trimethylsilazide, which proves that the active azide CPVC material is formed by the reaction, rather than a mixture of CPVC and trimethylsilazide; S3, after the activation reaction, the stirring speed is reduced to 200 rpm, the material temperature is cooled to 38℃, the selected grafting reaction aid is added to the mixer, and the grafting reaction aid is reacted with the activated chlorinated polyvinyl chloride to complete the grafting modification in 2 hours, and the chlorinated polyvinyl amine grafting modified product is obtained; Figure 2 The infrared spectrum of the chlorinated polyvinyl amine grafting modified product is shown in the figure, and the absorption peak marked in the figure is the absorption peak of the grafting to the CPVC group. The absorption peak indicates the existence of NH, which indicates that the amine group (-NH2) of the grafting material reacts with the active group of CPVC to form NH; S4, the prepared stabilizer, lubricant, impact modifier, processing aid, filler are sequentially added to the chlorinated polyvinyl amine grafting modified product, and fully stirred at a speed of 600 rpm to raise the temperature to 120℃. After ensuring uniform dispersion, the crosslinking aid is added, and stirred to 130℃, then the material is immediately placed in a cooling mixer for rapid cooling. After adding the composite foaming agent, continue to stir until the material temperature is 38℃, forming the foaming mixture; the mixture is discharged from the cooling mixer and cooled for standby; the high-speed mixer and the cooling mixer are equipped with two layers of stirring paddles, which are staggered in a cross shape, and the top cover plate is provided with a spoiler; S5, the foaming forming processing equipment is an extruder (the extruder is a conical twin-screw extruder with a length-diameter ratio of 16:1, and the die set thickness is 4 mm), the temperature range of the extruder is set to 170-175 DEG C, the die temperature is 180-184 DEG C, under the high temperature, the foaming agent azodicarbonamide (ADC) and sodium bicarbonate are decomposed to produce gas under the action of a catalyst, at the same time, the crosslinking aid of diacid and the grafted and modified product of chlorinated polyvinylamine are condensed to form crosslinking bonds, the two processes occur synchronously, the gas makes the material expand to form a bubble structure, and the condensation crosslinking reaction forms a network structure between molecules to stabilize the bubble; after foaming forming and cooling and shaping, the final chlorinated polyvinyl chloride grafted and crosslinked foaming material product is obtained, and the reference Figure 3 The bubble structure of the foaming material product is fine and uniform.
[0024] Example 2 S1, the raw material components are weighed according to the formula; S2, the chlorinated polyvinyl chloride resin is put into a sealed high-speed mixer, and the mixer is started to stir; the weighed trimethylsilazide and the selected catalyst are pre-mixed, and slowly added to the chlorinated polyvinyl chloride resin in the mixer; the stirring speed of the mixer is controlled to 400 rpm, the material is gradually heated and stabilized at 70 DEG C, under this condition, the stirring reaction is continued for 2 hours, so that the trimethylsilazide and the chlorinated polyvinyl chloride molecular chain occur substitution reaction, and the resin is activated; S3, after the activation reaction, the stirring speed is reduced to 250 rpm, the material temperature is cooled to 38 DEG C, the selected grafting reaction aid is added to the mixer, and the grafting reaction aid is reacted with the activated chlorinated polyvinyl chloride to form a grafting reaction aid, and the grafting modification is completed after 1.5 hours of stirring, and the chlorinated polyvinylamine grafted and modified product is obtained; S4, the prepared stabilizer, lubricant, impact modifier, processing aid, filler are added to the chlorinated polyvinylamine grafted and modified product in sequence, and fully stirred at a speed of 750 rpm to raise the temperature to 120 DEG C. After ensuring uniform dispersion, the crosslinking aid is added, and stirred to 125 DEG C, and then the material is quickly cooled in a cooling mixer, and after adding the composite foaming agent, the stirring is continued until the material temperature is 38 DEG C, and the foaming mixture is formed; the mixture is discharged from the cooling mixer and cooled for standby; the high-speed mixer and the cooling mixer are the same as in example 1; S5. The foaming molding equipment is an extruder (the same as in Example 1). The extruder temperature range is set to 170-186°C, and the die temperature is set to 180-188°C. At this high temperature, the foaming agent azodicarbonamide (ADC) and sodium bicarbonate decompose to generate gas under the action of a catalyst. At the same time, the diacid crosslinking aid and the chlorinated polyvinyl chloride amine graft modification product undergo a condensation reaction to form crosslinking bonds. These two processes occur simultaneously. The gas causes the material to expand and form a cell structure, while the condensation crosslinking reaction forms a network structure between molecules, stabilizing the cells. After foaming molding and cooling, the final chlorinated polyvinyl chloride graft crosslinked foam material product can be obtained.
[0025] Example 3 S1. Weigh the raw material components according to the formula; S2. Add the chlorinated polyvinyl chloride resin into a closed high-speed mixer and start the mixer to stir. Premix the weighed trimethylsilyl azide with the selected catalyst and slowly add it into the chlorinated polyvinyl chloride resin in the mixer. Control the stirring speed of the mixer to 450 rpm, so that the material gradually heats up and stabilizes at 75°C. Under this condition, continue stirring and reacting for 1 hour to allow the trimethylsilyl azide to undergo a substitution reaction with the chlorinated polyvinyl chloride molecular chain, thereby activating the resin. S3. After activation reaction, reduce stirring speed to 200 rpm, cool material temperature to 38℃, add selected grafting reaction aid to mixer, stir to make grafting reaction aid react with activated chlorinated polyvinyl chloride, stir for 1.5 hours to complete grafting modification, and obtain chlorinated polyvinyl chloride amine grafted modified product. S4. Add the prepared stabilizer, lubricant, impact modifier, processing aid, and filler sequentially to the chlorinated polyvinyl chloride amine graft-modified product. Stir thoroughly at 750 rpm until the temperature rises to 115°C. After ensuring uniform dispersion, add the crosslinking aid and stir until the temperature reaches 125°C. Immediately transfer the material to a cooling mixer for rapid cooling. After adding the composite foaming agent, continue stirring until the material temperature reaches 38°C, forming a foaming mixture. Discharge the mixture from the cooling mixer and allow it to cool for later use. The high-speed mixer and cooling mixer are the same as those used in Example 1. S5. The foaming molding equipment is an extruder (same as in Example 1). The extruder temperature range is set to 175-182°C, and the die temperature is set to 184-188°C. At this high temperature, the foaming agent azodicarbonamide (ADC) and sodium bicarbonate decompose to generate gas under the action of a catalyst. At the same time, the diacid crosslinking aid and the chlorinated polyvinyl chloride amine graft modification product undergo a condensation reaction to form crosslinking bonds. These two processes occur simultaneously. The gas causes the material to expand and form a cell structure, while the condensation crosslinking reaction forms a network structure between molecules, stabilizing the cells. After foaming molding and cooling, the final chlorinated polyvinyl chloride graft crosslinked foam material product can be obtained.
[0026] Comparative Example 1 This comparative example is compared with Example 1.
[0027] (1) Weigh the raw material components according to the formula; (2) Add chlorinated polyvinyl chloride resin into a closed high-speed mixer and start the mixer to stir. Add the prepared stabilizer, lubricant, impact modifier, processing aid and filler in sequence. Stir thoroughly at 750 rpm until the temperature rises to 120°C. Immediately put the material into a cooling mixer to cool it down quickly. Add the composite foaming agent and continue stirring until the material temperature reaches 38°C to form a mixture to be foamed. Release the mixture from the cooling mixer and let it cool for later use. The high-speed mixer and cooling mixer are the same as in Example 1. (3) The foaming molding equipment is an extruder (same as in Example 1). The extruder temperature range is set to 170-175℃, and the die temperature is set to 180-184℃. At this high temperature, the foaming agent azodicarbonamide (ADC) and sodium bicarbonate decompose to produce gas under the action of the additives. The material expands to form a cell structure. After foaming molding and cooling, chlorinated polyvinyl chloride foamed material products are obtained. (Refer to...) Figure 4 The foamed material has a relatively rough and irregular cell structure.
[0028] Comparative Example 2 This comparative example is compared with Example 2.
[0029] (1) Weigh the raw material components according to the formula; (2) Add chlorinated polyvinyl chloride resin into a closed high-speed mixer and start the mixer to stir. Add the prepared stabilizer, lubricant, impact modifier, processing aid and filler in sequence. Stir thoroughly at 680 rpm until the temperature rises to 120°C. Immediately put the material into a cooling mixer to cool it down quickly. Add the composite foaming agent and continue stirring until the material temperature reaches 38°C to form a mixture to be foamed. Release the mixture from the cooling mixer and let it cool for later use. The high-speed mixer and cooling mixer are the same as in Example 1. (3) The foaming molding equipment is an extruder (same as in Example 1). The extruder temperature range is set to 174-180°C, and the die temperature is set to 180-188°C. At this high temperature, the foaming agent azodicarbonamide (ADC) and sodium bicarbonate decompose to produce gas under the action of the additives. The material expands to form a cell structure. After foaming molding and cooling, chlorinated polyvinyl chloride foamed material products are obtained. Comparative Example 3 This comparative example is compared with Example 3.
[0030] (1) Weigh the raw material components according to the formula; (2) Put the chlorinated polyvinyl chloride resin into a closed high-speed mixer, and start the mixer to stir. Add the prepared stabilizer, lubricant, impact modifier, processing aid, and filler in sequence, and fully stir at a speed of 600 rpm until the temperature rises to 115°C. Immediately put the material into a cooling mixer for rapid cooling, add the composite foaming agent, and continue to stir and mix until the material temperature is 38°C to form the mixed material to be foamed; take out the mixed material from the cooling mixer, and cool for standby; the high-speed mixer and the cooling mixer are the same as in Example 1; (3) The foaming molding processing equipment is an extruder (the same as in Example 1), and the temperature range of the extruder is set to 175-182°C, and the die temperature is 180-184°C. Under the high temperature, the foaming agent azodicarbonamide (ADC) and sodium bicarbonate decompose to generate gas under the action of the aid, the material expands to form a bubble structure, and after foaming molding and cooling and shaping, the chlorinated polyvinyl chloride foaming material product is obtained.
[0031] The foaming material products prepared in Examples 1-3 and Comparative Examples 1-3 are respectively made into test pieces for sample preparation, and the HDT heat distortion temperature, tensile strength, tensile modulus, compression strength, compression modulus, shear modulus, shear deformation, and combustion performance are tested. The test results are shown in Table 2.
[0032] Table 2 As shown in Table 2, the chlorinated polyvinyl chloride grafting crosslinking foaming material prepared in Examples 1-3 has obvious improvement in tensile strength, tensile modulus, compression strength, compression modulus, and shear modulus, and the improvement ratio reaches 20-30%, compared with the foaming material products prepared by the non-crosslinking formula in Comparative Examples 1-3. The improvement in performance also significantly improves the heat distortion temperature of the material, so that it can still maintain shape stability at a higher temperature environment. Under the condition that the foaming densities are similar, the heat distortion temperature of the CPVC foaming material after grafting and crosslinking is obviously improved, and the improvement amplitude is 4-6°C. At the same time, the shear strain performance is also improved, which indicates that the product has high strength and good stiffness after grafting and crosslinking, meaning that the material has better toughness or deformation recovery capacity.
[0033] The above examples are preferred embodiments of the present application, but the embodiments of the present application are not limited to the above examples. Any changes, modifications, substitutions, combinations, simplifications made without departing from the spirit and principles of the present application shall be equivalent replacement methods, and all shall be included in the protection scope of the present application.
Claims
1. A chlorinated polyvinyl chloride grafted crosslinked foam material, characterized in that, It is composed of the following raw materials in parts by weight: 95-105 parts of chlorinated polyvinyl chloride, 1-3 parts of trimethylsilyl azide, 0.5-2 parts of organotin catalyst, 2-4 parts of grafting reaction aid, 4.5-7.5 parts of crosslinking aid, 2-10 parts of composite foaming agent, 4-7 parts of stabilizer, 1.5-3 parts of impact modifier, 1-2.5 parts of processing aid, 1-2.5 parts of lubricant, and 3-5.5 parts of filler.
2. The chlorinated polyvinyl chloride grafted crosslinked foam material as described in claim 1, characterized in that: The chlorinated polyvinyl chloride has a chlorine content ranging from 60% to 65% and a melt viscosity of 1600 to 1800 Pa·s.
3. The chlorinated polyvinyl chloride grafted crosslinked foam material as described in claim 1, characterized in that: The organotin catalyst is one of dibutyltin dilaurate and di(dodecylthio)dibutyltin.
4. The chlorinated polyvinyl chloride grafted crosslinked foam material as described in claim 1, characterized in that: The grafting reaction aid is one of hexamethylenediamine or tetramethylmethanediamine.
5. The chlorinated polyvinyl chloride grafted crosslinked foam material as described in claim 1, characterized in that: The crosslinking aid is one of octadecanoic acid, tetradecanoic acid, and dodecanoic acid.
6. The chlorinated polyvinyl chloride grafted crosslinked foam material as described in claim 1, characterized in that: The composite foaming agent is composed of a main foaming agent, an auxiliary foaming agent, and a foaming aid in a mass ratio of 1–5:0.8–4.5:1.4–2.5; the main foaming agent is azodicarbonamide; the auxiliary foaming agent is sodium bicarbonate; and the foaming aid is composed of zinc oxide, zinc stearate, stearic acid, palmitic acid, and a foaming regulator in a mass ratio of 0.2–0.4:0.4–0.8:0–0.8:0–1:0.3–0.
5.
7. The chlorinated polyvinyl chloride grafted crosslinked foam material as described in claim 1, characterized in that: The stabilizer includes a primary stabilizer and an auxiliary stabilizer. The primary stabilizer is one of methyltin mercaptan, butyltin mercaptan, butyltin laurate, and butyltin maleate. The auxiliary stabilizer is one or a combination of two or more of antioxidant 1010, epoxidized soybean oil, and hydrotalcite in any proportion.
8. The chlorinated polyvinyl chloride grafted crosslinked foam material as described in claim 1, characterized in that: The impact modifier is one or a combination of two of the following in any proportion: acrylate impact modifier and methyl methacrylate-butadiene-styrene copolymer.
9. The chlorinated polyvinyl chloride grafted crosslinked foam material as described in claim 1, characterized in that: The lubricant is a combination of one or more of paraffin wax, polyethylene wax, fatty acid complex alcohol ester, chlorinated paraffin, and Fischer-Tropsch wax in any proportion; the filler is a combination of one or more of titanium dioxide and nano-calcium carbonate in any proportion.
10. A method for preparing a chlorinated polyvinyl chloride grafted crosslinked foam material according to any one of claims 1 to 9, comprising the following steps: S1. Weigh out each raw material according to the mass fraction, put the chlorinated polyvinyl chloride resin into a closed mixer, and start the mixer to stir; premix the trimethylsilazine and organotin catalyst, and slowly add them into the chlorinated polyvinyl chloride resin in the mixer, controlling the stirring speed of the mixer at 300-450 rpm, so that the material gradually heats up and stabilizes at 60-75℃. Under these conditions, continue stirring and reacting for 2-2.5 hours to allow the trimethylsilazine to undergo a substitution reaction with the chlorinated polyvinyl chloride molecular chain, thereby activating the resin; S2. After activation reaction, reduce stirring speed to 200-300 rpm, cool material temperature to below 40℃, add grafting reaction aid to mixer, so that grafting reaction aid reacts with activated chlorinated polyvinyl chloride, stir for 1-2 hours to complete grafting modification, and obtain chlorinated polyvinyl chloride amine grafted modified product. S3. Add stabilizer, lubricant, impact modifier, processing aid, and filler sequentially to the chlorinated polyvinyl chloride amine graft-modified product. Stir thoroughly at 600-750 rpm until the temperature rises to 115-120℃, ensuring uniform dispersion. Then add crosslinking aid and stir until the temperature reaches 125-130℃. Immediately transfer the material to a cooling mixer for rapid cooling. Add composite foaming agent and continue stirring until the material temperature is below 40℃, forming a mixture to be foamed. Remove the mixture from the cooling mixer and allow it to cool for later use. S4. Set the processing temperature to 170-188℃. The foaming agent azodicarbonamide and sodium bicarbonate decompose to generate gas under the action of a catalyst. At the same time, the crosslinking aid and the chlorinated polyvinyl chloride amine graft modification product undergo a condensation reaction to form crosslinking bonds. These two processes occur simultaneously. The gas causes the material to expand and form a cell structure, while the condensation crosslinking reaction forms a network structure between molecules, stabilizing the cells. After foaming, molding and cooling, the final chlorinated polyvinyl chloride graft crosslinked foam material product can be obtained.