Flexible polyvinyl chloride composition as well as preparation method and application thereof

Abstract

The invention discloses a flexible polyvinyl chloride composition as well as a preparation method and application thereof, and belongs to the technical field of high polymer materials. The flexible polyvinyl chloride composition comprises the following components in parts by weight: 100 parts of polyvinyl chloride resin; 40 to 55 parts of a flexible modifier; 2-3 parts of a stabilizer; 1-2 parts of a lubricant; 10-15 parts of an inorganic filler; 15-25 parts of a plasticizer; wherein the flexibility modifier is a mixture of maleic anhydride grafted linear low density polyethylene, chlorinated polyethylene and an acrylate impact modifier. According to the flexible polyvinyl chloride composition provided by the invention, by adding the specific flexibility modifier, the polyvinyl chloride composition has excellent flexibility, has good deformability in construction, installation and use processes, and is not easy to crack when being impacted. The method can be widely applied to preparation of flexible PVC drainage pipe fittings and other products.

Description

Technical Field

[0001] The present invention relates to the technical field of polymer materials, and more specifically to a flexible polyvinyl chloride composition and a preparation method and application thereof. Background Art

[0002] Polyvinyl chloride materials are cheap and have good flame retardant properties. The current annual domestic production is about 20 million tons, of which a large number are used in building drainage and other fields. However, the current rigid polyvinyl chloride (PVC-U) drainage pipe fittings have the following main disadvantages: rigid polyvinyl chloride (PVC-U) has poor flexibility, especially after being prepared into drainage pipe fittings, due to the complex structure, it is easy to have residual stress, etc., and the rigid polyvinyl chloride (PVC-U) itself has material defects, and it is easy to break when subjected to external impact.

[0003] Moreover, in the actual construction and installation process of PVC-U pipes, glue is mostly used for bonding. Glue contains organic solvent components, and the production and construction and installation process will affect people's health. In addition, glue bonding is a fixed connection. In order to solve the thermal expansion and contraction of the pipe, it is necessary to add special rubber ring connection pipe fittings to the pipe system. Furthermore, the glue cannot be detached after curing, which affects the convenience of later pipeline maintenance.

[0004] Prior art CN117683304A discloses a PVC material and its preparation method and application, which comprises the following components by mass: 100 parts of polyvinyl chloride resin, 5-20 parts of flame retardant high temperature toughening powder, 2-8 parts of zinc flame retardant, 2-8 parts of impact modifier, 8.5-35 parts of other additives, wherein the impact modifier is one or more of chlorinated polyethylene, acrylic polymer and methyl methacrylate-butadiene-styrene terpolymer. Although the impact modifier is added to improve the impact resistance, the flexibility of the PVC material cannot be significantly improved. Summary of the invention

[0005] The technical problem to be solved by the present invention is to overcome the defects and shortcomings of the existing polyvinyl chloride compositions for preparing PVC drainage pipes, such as poor flexibility and easy rupture when deformed, and to provide a flexible polyvinyl chloride composition. By adding a specific flexibility modifier, the polyvinyl chloride composition has excellent flexibility, good deformation ability during construction, installation and use, and is not easy to rupture when impacted.

[0006] Another object of the present invention is to provide a method for preparing a flexible polyvinyl chloride composition.

[0007] Another object of the present invention is to provide an application of a flexible polyvinyl chloride composition in the preparation of flexible PVC drainage pipe fittings.

[0008] The above-mentioned purpose of the present invention is achieved through the following technical solutions:

[0009] A flexible polyvinyl chloride composition, comprising the following components by weight:

[0010]

[0011] Wherein, the flexibility modifier is a mixture of maleic anhydride grafted linear low-density polyethylene, chlorinated polyethylene and acrylate impact modifier;

[0012] The weight percentage of maleic anhydride grafted linear low-density polyethylene in the flexibility modifier is 25-50%.

[0013] The invention provides a flexible polyvinyl chloride composition. By adding a specific flexible modifier, the polyvinyl chloride composition has excellent flexibility, good deformation ability during construction, installation and use, and is not prone to cracking when impacted.

[0014] In the flexibility modifier of the present invention, since the maleic anhydride grafted linear low-density polyethylene has a polar structure with anhydride functional groups, it can be integrated with polar polyvinyl chloride resin and combined with chlorinated polyethylene and acrylate impact modifier to improve the flexibility of the polyvinyl chloride composition, especially the elongation at break.

[0015] Although the flexibility modifier can improve the flexibility of the composition, especially the improvement of the elongation at break and the excellent impact resistance and deformation capacity, too much flexibility modifier can also cause the product to be insufficient in strength and fail to meet the requirements of building pipes.

[0016] Moreover, the amount of maleic anhydride grafted linear low-density polyethylene in the flexibility modifier needs to be controlled within a certain range. Too much maleic anhydride grafted linear low-density polyethylene will cause insufficient rigidity of the material and adhesion to the screw mold. Too little maleic anhydride grafted linear low-density polyethylene will make it difficult to improve the flexibility of the polyvinyl chloride composition.

[0017] In a specific embodiment, the flexibility modifier may be 40 parts, 45 parts, 50 parts, or 55 parts.

[0018] In specific embodiments, the amount of plasticizer may be 15 parts, 18 parts, 20 parts, 22 parts, or 55 parts.

[0019] In a specific embodiment, the weight percentage of the maleic anhydride grafted linear low density polyethylene in the flexibility modifier can be 25%, 30%, 35%, 40%, 45%, or 50%.

[0020] Preferably, the weight percentage of chlorinated polyethylene in the flexibility modifier is not more than 65%.

[0021] Preferably, the weight percentage of chlorinated polyethylene in the flexibility modifier is 30-65%.

[0022] In a specific embodiment, the weight percentage of chlorinated polyethylene in the flexibility modifier can be 30%, 35%, 40%, 45%, 50%, 55%, 60%, or 65%.

[0023] Preferably, the weight percentage of the acrylic ester impact modifier in the flexibility modifier is 8 to 35%.

[0024] Preferably, in the maleic anhydride grafted linear low-density polyethylene, the mass grafting rate of maleic anhydride is 0.4-1.2%.

[0025] In a specific embodiment, the mass grafting rate of maleic anhydride is 0.4%, 0.6%, 0.8%, 1.0%, or 1.2%.

[0026] More preferably, the mass grafting rate of maleic anhydride in the maleic anhydride-grafted linear low-density polyethylene is 0.8 to 1.0%.

[0027] The test method for the mass grafting rate of maleic anhydride is the acid-base titration method.

[0028] In maleic anhydride grafted linear low-density polyethylene, the mass grafting rate of maleic anhydride will also affect the fusion and processing properties of the composition. A larger mass grafting rate of maleic anhydride is beneficial to the compatibility of maleic anhydride-modified linear low-density polyethylene with polyvinyl chloride resin, thereby improving the flexibility of the composition, that is, improving the elongation at break, and preventing the occurrence of cold spots. A smaller mass grafting rate of maleic anhydride is beneficial to reducing the adhesion of the modified material to equipment such as screw molds, preventing the generation of carbonized black spots, and improving processing performance.

[0029] Preferably, the maleic anhydride grafted linear low density polyethylene has a melt mass flow rate of 1.0 to 1.7 g / 10 min at 190° C. and 2.16 kg.

[0030] The test standard for melt mass flow rate is GBT 3682.1-2018.

[0031] In the maleic anhydride grafted linear low-density polyethylene, the melt mass flow rate of the maleic anhydride grafted linear low-density polyethylene will also affect the mechanical properties of the composition. A larger mass flow rate is beneficial to improving the tensile strength of the material, while a smaller mass flow rate is beneficial to improving the fluidity of the material.

[0032] Preferably, the lubricant is a mixture of glycerol montanate, ethylene glycol montanate and oxidized polyethylene wax, and the weight ratio of glycerol montanate, ethylene glycol montanate and oxidized polyethylene wax is (0.7-0.9):(0.4-0.6):1.

[0033] In a specific embodiment, the weight ratio of glycerol montanate, ethylene glycol montanate and oxidized polyethylene wax is 0.7:0.4:1, 0.7:0.6:1, 0.9:0.4:1, 0.9:0.6:1, 0.8:0.5:1.

[0034] Glycerol montanate and ethylene glycol montanate act as internal lubricants for polyvinyl chloride.

[0035] Compared with the common internal lubricants stearic acid or monoglyceride in the art, glyceryl montanate and ethylene glycol montanate have more excellent processing demoulding performance and anti-migration properties, can prevent the phenomenon of "frosting" precipitation, thereby improving the apparent quality, and are beneficial to improving the gloss.

[0036] Preferably, the polyvinyl chloride resin can be a mixture of type VIII suspension polyvinyl chloride (PVC-SG8) and type V suspension polyvinyl chloride (PVC-SG5). The viscosity of type VIII suspension polyvinyl chloride is 73-86 mL / g, and the viscosity of type V suspension polyvinyl chloride is 107-118 mL / g. The weight percentage of type V suspension polyvinyl chloride in the polyvinyl chloride resin is 0-0.15%.

[0037] The weight ratio of type VIII suspension polyvinyl chloride to type V suspension polyvinyl chloride can be 1: (4-8). An appropriate amount of type V suspension polyvinyl chloride is beneficial to improving the tensile properties of the polyvinyl chloride composition. More type V suspension polyvinyl chloride will reduce fluidity and make injection molding processing difficult.

[0038] Preferably, the plasticizer is epoxy fatty acid methyl ester, which is non-toxic, hygienic, environmentally friendly and low in price.

[0039] Plasticizers can adjust the Shore hardness of polyvinyl chloride compositions, especially those made into pipes.

[0040] The hardness of pipe fittings is related to their deformation capacity. The smaller the hardness, the better the deformation capacity.

[0041] Preferably, the stabilizer is an organotin stabilizer.

[0042] The organotin stabilizer may specifically be methyl tin mercaptan.

[0043] Preferably, the inorganic filler is one or more of titanium dioxide and calcium carbonate.

[0044] The present invention also protects a method for preparing the above-mentioned flexible polyvinyl chloride composition, which comprises the following steps: mixing the components to obtain the flexible polyvinyl chloride composition.

[0045] The present invention also protects the use of the above-mentioned flexible polyvinyl chloride composition in the preparation of PVC drainage pipe fittings.

[0046] Compared with the prior art, the present invention has the following beneficial effects:

[0047] The present invention provides a flexible polyvinyl chloride composition, which has excellent flexibility by adding a specific flexibility modifier, has good deformation ability during construction, installation and use, and is not easy to break when impacted. It can be widely used in the preparation of PVC drainage pipe fittings. DETAILED DESCRIPTION

[0048] The present invention is further described below in conjunction with specific embodiments, but the embodiments do not limit the present invention in any form. Unless otherwise specified, the raw materials and reagents used in the embodiments of the present invention are conventionally purchased raw materials and reagents.

[0049] Polyvinyl chloride resin 1, type VIII suspension polyvinyl chloride resin, brand name SG-8.

[0050] Polyvinyl chloride resin 2, type V suspension polyvinyl chloride resin, brand name SG-5.

[0051] Chlorinated polyethylene, the manufacturer is Guangxi Tiandong Jinsheng Chemical, the brand is CPE-135A.

[0052] Core-shell structured acrylic impact modifier, manufactured by Shandong Riko Chemical, brand ACM-24.

[0053] Maleic anhydride grafted linear low density polyethylene 1, manufacturer is Coase Chemical, brand: TDS-W1L.

[0054] The mass grafting rate of maleic anhydride was 0.8%, and the melt mass flow rate of the maleic anhydride grafted linear low density polyethylene at 190° C. and 2.16 kg was 1.7 g / 10 min.

[0055] The maleic anhydride grafted linear low-density polyethylene 2 was customized by Coase Chemical, and the difference from the maleic anhydride grafted linear low-density polyethylene 1 was that the mass grafting rate of maleic anhydride was 0.4%.

[0056] The maleic anhydride grafted linear low-density polyethylene 3 was customized by Coase Chemical, and the difference from the maleic anhydride grafted linear low-density polyethylene 1 was that the mass grafting rate of maleic anhydride was 0.6%.

[0057] The maleic anhydride grafted linear low-density polyethylene 4 was customized by Coase Chemical, and the difference from the maleic anhydride grafted linear low-density polyethylene 1 was that the mass grafting rate of maleic anhydride was 1.0%.

[0058] The maleic anhydride grafted linear low-density polyethylene 5 was customized by Coase Chemical, and the difference from the maleic anhydride grafted linear low-density polyethylene 1 was that the mass grafting rate of maleic anhydride was 1.2%.

[0059] Stabilizer: tin methyl mercaptan.

[0060] External lubricant, oxidized polyethylene wax.

[0061] Internal lubricant 1, glyceryl montanate.

[0062] Internal lubricant 2, ethylene glycol montanate.

[0063] Internal lubricant 3, monoglyceride of fatty acid.

[0064] Inorganic filler 1, pigment titanium dioxide.

[0065] Inorganic filler 2, calcium carbonate.

[0066] Plasticizer, epoxy fatty acid methyl ester.

[0067] Examples 1 to 10

[0068] A flexible polyvinyl chloride composition, comprising the following components by weight:

[0069] Polyvinyl chloride resin; flexibility modifier; stabilizer; lubricant; inorganic filler; plasticizer;

[0070] The flexibility modifier is a mixture of maleic anhydride grafted linear low-density polyethylene, chlorinated polyethylene and acrylic ester impact modifier, wherein the specific content of each component is shown in Table 1 below.

[0071] Table 1 Composition of the flexible polyvinyl chloride composition of each embodiment (by weight)

[0072]

[0073]

[0074] Table 1

[0075]

[0076]

[0077] The preparation method of the above-mentioned flexible polyvinyl chloride composition is specifically as follows:

[0078] Put polyvinyl chloride resin, stabilizer, lubricant, flexibility modifier and inorganic filler into a high-speed mixer in the formulated ratio and mix them at high speed for 3 minutes. Then add plasticizer and continue mixing at high speed until the temperature reaches 115°C. After reaching the temperature, discharge it into a low-speed mixer and cool and stir it to 55°C to obtain a flexible polyvinyl chloride composition dry blend.

[0079] Comparative Examples 1-2

[0080] A polyvinyl chloride composition, comprising the following components by weight:

[0081] Polyvinyl chloride resin; flexibility modifier; stabilizer; lubricant; inorganic filler; plasticizer;

[0082] The flexibility modifier is a mixture of maleic anhydride grafted linear low-density polyethylene, chlorinated polyethylene and acrylic ester impact modifier, wherein the specific content of each component is shown in Table 2 below.

[0083] Table 2 Composition of polyvinyl chloride compositions of various comparative examples (by weight)

[0084]

[0085]

[0086] The preparation method of the polyvinyl chloride composition is the same as that in the embodiment.

[0087] Results

[0088] The dry blend of the polyvinyl chloride composition prepared in the examples and comparative examples was plasticized at 185° C. and 45 rpm for 12 minutes using a rheometer to obtain a melt, which was then pressed into a test specimen on a specimen mold of a flat vulcanizer for the following test.

[0089] (1) Elongation at break test: The test standard is GB / T 8804.2-2003.

[0090] (2) Tensile yield stress: The test standard is GB / T 8804.2-2003.

[0091] (3) Shore A hardness: Test standard GB / T 531.1-2008.

[0092] The polyvinyl chloride composition dry blends of the above examples and comparative examples were prepared into PVC pipe fittings and subjected to the following tests:

[0093] (4) Injection molding processability of dry blends: According to the UL94-2022 standard, the thickness of the test specimen is 3.2 mm.

[0094] (5) Dry mix injection molding yield (%): The calculation method is the ratio of the weight of the finished pipe to the weight of the input raw materials.

[0095] (6) Water tightness test: The test standard is GB / T 5836.2-2018.

[0096] (7) Air tightness test: The test standard is GB / T 5836.2-2018.

[0097] (8) Freezing drop test: The test standard is GBT 3682.1-2018.

[0098] The specific test results of each embodiment are described in Table 3 below:

[0099] Table 3

[0100]

[0101]

[0102] Table 3

[0103]

[0104]

[0105] The specific test results of each comparative example are described in Table 4 below:

[0106] Table 4

[0107] project Comparative Example 1 Comparative Example 2 <![CDATA[Density g / cm 3 > 1.459 1.462 Tensile yield stress MPa 23.6 28.1 Elongation at break % 115.3 85.2 Vicat softening temperature℃ 65.1 69.8 Shore A Hardness 66.5 78.9 Melt mass flow rate g / 10min 5.1 2.2 Frozen Fall 23 Failure Dry blend injection molding processability easy difficulty Dry mix injection molding yield (including gate) % 82.3 77.2 System water tightness test Failure Failure System air tightness test Failure Failure Appearance (visual observation) Generally, there are cold spots Poor, severe cold spots

[0108] From the above data, it can be seen that the flexible polyvinyl chloride composition of the present invention has a Vicat softening temperature lower than 70.8°C by adding a specific flexibility modifier, the material is relatively soft, the Shore A hardness is lower than 79.6, it has a high deformation capacity, and the elongation at break can reach more than 145%, so that the polyvinyl chloride composition has excellent flexibility and is not easy to break when impacted. It can be widely used in the preparation of PVC drainage pipes.

[0109] It can be seen from Examples 1 and 3 that the polyvinyl chloride resin is a mixture of type VIII suspension polyvinyl chloride and type V suspension polyvinyl chloride, and the weight percentage of type V suspension polyvinyl chloride in the polyvinyl chloride resin is 0 to 0.15%, which is more conducive to improving the tensile yield stress of the polyvinyl chloride composition.

[0110] It can be seen from Examples 1 and 6 to 9 that the mass grafting rate of maleic anhydride in the maleic anhydride grafted linear low-density polyethylene is 0.8 to 1.0%, which is more conducive to improving the flexibility of the composition, that is, improving the elongation at break, and can prevent the occurrence of cold spots, and is also conducive to reducing the adhesion of the material to equipment such as screw molds, preventing the generation of carbonized black spots, and improving processing performance.

[0111] It can be seen from Example 1 and Example 10 that, compared with stearic acid, which is a common internal lubricant in the art, glycerol montanate and ethylene glycol montanate as lubricants have more excellent processing and demoulding properties, and are beneficial for improving gloss.

[0112] It can be seen from the examples and comparative example 1 that without adding a flexibility modifier, the polyvinyl chloride composition is soft, but the elongation at break is too low, that is, the toughness is insufficient, and the system air tightness test and the system water tightness test are unqualified, indicating that the sealing requirements of the polyvinyl chloride drain pipe cannot be met.

[0113] It can be seen from the embodiment and comparative example 2 that without adding maleic anhydride grafted linear low-density polyethylene, a large amount of chlorinated polyethylene in the composition will cause a decrease in processability and elongation at break, and the system air tightness test and the system water tightness test will fail, indicating that the sealing requirements of the polyvinyl chloride drain pipe cannot be met.

[0114] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the embodiments of the present invention. For those skilled in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the embodiments here. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the claims of the present invention.

Claims

1. A flexible polyvinyl chloride composition, characterized in that: By weight, it includes the following components: Wherein, the flexibility modifier is a mixture of maleic anhydride grafted linear low-density polyethylene, chlorinated polyethylene and acrylate impact modifier; The weight percentage of maleic anhydride grafted linear low-density polyethylene in the flexibility modifier is 25-50%.

2. The flexible polyvinyl chloride composition according to claim 1, characterized in that: The weight percentage of chlorinated polyethylene in the flexibility modifier is 30-65%.

3. The flexible polyvinyl chloride composition according to claim 1, characterized in that: In the maleic anhydride grafted linear low density polyethylene, the mass grafting rate of maleic anhydride is 0.4 to 1.2%.

4. The flexible polyvinyl chloride composition according to claim 1, characterized in that: The lubricant is a mixture of glycerol montanate, ethylene glycol montanate and oxidized polyethylene wax, and the weight ratio of glycerol montanate, ethylene glycol montanate and oxidized polyethylene wax is (0.5-1):(0.3-0.8):

1.

5. The flexible polyvinyl chloride composition according to claim 1, characterized in that: The polyvinyl chloride resin is a mixture of type VIII suspension polyvinyl chloride and type V suspension polyvinyl chloride, and the weight percentage of type V suspension polyvinyl chloride in the polyvinyl chloride resin is 0-0.15%.

6. The flexible polyvinyl chloride composition according to claim 1, characterized in that: The plasticizer is epoxy fatty acid methyl ester.

7. The flexible polyvinyl chloride composition according to claim 1, characterized in that: The stabilizer is an organotin stabilizer.

8. The flexible polyvinyl chloride composition according to claim 1, characterized in that: The inorganic filler is one or more of titanium dioxide and calcium carbonate.

9. The method for preparing the flexible polyvinyl chloride composition according to any one of claims 1 to 8, characterized in that: The method comprises the following steps: mixing the components to obtain the flexible polyvinyl chloride composition.

10. Use of the flexible polyvinyl chloride composition according to any one of claims 1 to 8 in the preparation of PVC drainage pipes.

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