High-elasticity and high-stability PVC (Polyvinyl Chloride) aggregate as well as preparation method and application thereof

Abstract

The invention belongs to the technical field of high polymer material modification, and relates to a high-elasticity and high-stability PVC (Polyvinyl Chloride) granule, a preparation method and application in a medical catheter. The granules are prepared from the following raw materials in parts by weight: 100 parts of PVC resin powder, 50-60 parts of a plasticizer, 5-10 parts of epoxidized soybean oil, 0.6-1.5 parts of a composite heat stabilizer, 0.4-6 parts of an elastomer, 0.4-0.8 part of a processing aid and 0.1-0.4 part of a lubricant, and the granules are obtained by pre-plasticizing the raw materials, performing melt extrusion through an extruder and performing granulation molding. A high-elasticity and high-stability medical catheter body can be obtained by carrying out melting secondary extrusion molding on the granules, a medical catheter product can be obtained by assembling the catheter body, and the medical catheter product comprises infusion, nursing or implantation intervention type medical catheters. The high-elasticity and high-stability PVC aggregate has excellent elasticity, tensile toughness, thermal stability and long-term stability, and can endow a catheter with excellent elasticity and stability when being applied to medical catheter products.

Description

Technical Field

[0001] The invention belongs to the technical field of polymer material modification, and relates to a high-elasticity and high-stability PVC granular material, a preparation method thereof, and an application thereof in a medical catheter. Background Art

[0002] Polyvinyl chloride (PVC) is one of the world's five most common plastics, widely used in various fields, and its production ranks second. It has excellent insulation and flame retardant properties. Since the PVC produced in the traditional industrial field inevitably has some defective structures, PVC will produce yellowing, discoloration and other degradation processes during use due to external effects such as light, oxygen, and heat, which reduces the original performance of PVC and limits the use of PVC. Therefore, it is necessary to improve the thermal stability of PVC.

[0003] It is generally believed that the degradation of PVC is a dehydrochlorination reaction of the PVC molecular chain, which forms double bonds on the molecular chain and accelerates the degradation of PVC. As the dehydrochlorination reaction proceeds, the conjugated double bonds on the PVC molecular chain gradually grow, which is manifested as a change in the color of the PVC material and a gradual deepening of the color; in addition, the hydrogen chloride released by the degradation of PVC has a catalytic effect on the degradation of PVC, further accelerating the degradation of PVC. Through patent and literature research, the main way to modify the thermal stability of PVC materials in the prior art is to quickly replace the allyl chloride on the PVC molecular chain, inhibit the growth of conjugated double bonds, fundamentally improve the thermal stability of PVC, and prevent PVC from discoloring; the second is to promptly absorb the hydrogen chloride released by the degradation of PVC to prevent its catalytic effect on the degradation of PVC, thereby slowing down the degradation of PVC. At present, the main method to improve the thermal stability of PVC is to add a certain amount of heat stabilizer to delay the thermal degradation of PVC.

[0004] Commonly used heat stabilizers include lead salts, metal soaps, organotin and rare earth heat stabilizers. However, the lead salt heat stabilizers used in traditional industrial production are too toxic and easily cause heavy metal pollution. The compatibility of metal soap heat stabilizers and resin matrix is ​​poor, making them difficult to process. Organotin heat stabilizers are expensive, have a strong odor during processing, and are prone to pollution. The use of rare earth heat stabilizers is also restricted due to regulation. Research on nitrogen-containing organic heat stabilizers has received much attention from researchers, but most organic heat stabilizers are small molecule compounds. Small molecule heat stabilizers are prone to precipitation, and have a general effect on improving the thermal stability of PVC. At the same time, the initial whiteness is general, and the color of the body sometimes affects the color of PVC products, and the long-term stability is insufficient.

[0005] Different products based on PVC have different performance and functional requirements for materials and products due to different application environments, such as high transparency, high elasticity, etc. However, while realizing some special functions of the products, these properties of the materials are often damaged, resulting in poor tensile toughness of the materials, which restricts its application and development in medical products with high performance requirements. For example, medical catheters may be squeezed and deformed during production and storage due to stockpiling and other needs. Poor material elasticity will cause the products to be folded, which will affect assembly and bonding. In severe cases, dissolution will occur. If this happens during the blood transfusion process, it will threaten the patient's life safety. Therefore, improving the long-term thermal stability of PVC materials while improving their elastic properties will be very important for product performance improvement and application. Summary of the invention

[0006] Based on this, the object of the present invention is to provide a high-elasticity and high-stability PVC granular material, which has excellent elastic properties, thermal stability and long-term stability.

[0007] The present invention also provides a preparation method of the high-elasticity and high-stability PVC granules and application thereof in medical device products.

[0008] To achieve the above object, the present invention adopts the following technical solutions: The invention provides a high-elasticity and high-stability PVC granules. Main raw materials include: 100 parts of PVC resin powder, 50-60 parts of plasticizer, 5-10 parts of epoxy soybean oil, 0.6-1.5 parts of composite heat stabilizer, 0.4-6 parts of elastomer, 0.4-0.8 parts of processing aid, and 0.1-0.4 parts of lubricant; the raw materials are calculated by weight.

[0009] Furthermore, the composite heat stabilizer comprises 5-7 parts of a main stabilizer and 3-5 parts of an auxiliary stabilizer; the main stabilizer is composed of zinc stearate and calcium stearate in a mass ratio of 1:1-5, and the auxiliary stabilizer comprises diisooctyl phosphite; the components are measured in parts by weight; the elastomer comprises chlorinated polyethylene, PVC elastomer or nitrile rubber; preferably, the chlorinated polyethylene and nitrile rubber are liquids, and the PVC elastomer is powder.

[0010] Further, the processing aid is formed by compounding acrylate copolymers of different molecular weights, and the acrylate copolymer is an ACR copolymer. The different molecular weights refer to high molecular weight, medium molecular weight and low molecular weight, preferably the high molecular weight is 15000-30000, the medium molecular weight is 10000-15000, and the low molecular weight is less than 10000; wherein the compounded ACR copolymer is preferably a compound of high molecular weight, medium molecular weight and low molecular weight in a mass ratio of 2:2:1; or a compound of high molecular weight and low molecular weight in a mass ratio of 3:1; or a compound of medium molecular weight and low molecular weight in a mass ratio of 3:1; wherein the high molecular weight ACR copolymer plays a role in toughening and impact resistance, the medium molecular weight ACR copolymer plays a role in enhancing melt strength, promoting plasticization and shortening processing time, and the low molecular weight ACR copolymer plays a role in auxiliary lubrication.

[0011] Furthermore, the average polymerization degree of the PVC resin powder is 1800-2500, preferably 2500; the plasticizer is an environmentally friendly non-phthalic plasticizer, including diisooctyl terephthalate (DOTP), dioctyl adipate (DOA) or trioctyl trimellitate (TOTM); the lubricant includes any one or more of oxidized polyethylene wax, stearic acid and benzyl silicone oil.

[0012] The present invention also provides a method for preparing high-elasticity and high-stability PVC granules, comprising the following steps: S1, first mixing solid raw materials, then mixing liquid raw materials and then mixing them with the solid raw materials in batches, controlling the mixing process, and obtaining pre-plasticized raw materials; S2, melt-extruding the pre-plasticized raw materials through an extruder, and granulating and forming the pre-plasticized raw materials.

[0013] Furthermore, the solid raw materials include PVC resin powder, stabilizers (zinc stearate, calcium stearate), processing aids (acrylate copolymers), lubricants (oxidized polyethylene wax, stearic acid), and powdered PVC elastomers; the liquid raw materials include plasticizers (di-ethylhexyl phthalate (DOTP), di-ethylhexyl adipate (DOA) or tri-ethylhexyl trimellitate (TOTM)), epoxy soybean oil, stabilizers (di-ethylhexyl phosphite), elastomers (liquid chlorinated polyethylene, liquid nitrile rubber), and lubricants (methylphenyl silicone oil).

[0014] Furthermore, the mixing process in S1 includes: S11, adding the solid raw material into a high mixing pot, setting the mixing speed to 200-300rpm / min, and after the solid raw material is heated to 50-80°C, adding 50%-80% of the liquid raw material; S12, after the temperature rises to 65-85°C, adding the remaining liquid raw material, continuing to stir and heating to 90-110°C, setting the mixing speed to 700-900rpm / min, and after the material temperature rises to 120-135°C, discharging the material, and finally cooling it to 45-65°C.

[0015] Furthermore, the granulation conditions of the extruder in S2 are: main engine speed 260±20rpm / min, feeding speed 160±20rpm / min, pelletizing speed 250±20rpm / min, and extrusion temperature 80-120°C.

[0016] The present invention further provides an application of high-elasticity and high-stability PVC granules in preparing a medical catheter body or catheter.

[0017] The present invention further provides a high-elasticity and high-stability medical catheter body, which is prepared by melt extrusion molding of high-elasticity and high-stability PVC granules as raw materials, and the extrusion molding conditions are: main machine speed 55±5rpm / min, traction speed 60±5rpm / min, and extruder temperature condition 135-155℃.

[0018] Finally, the present invention provides a high-elasticity and high-stability medical catheter, which is obtained by assembling the high-elasticity and high-stability medical catheter body as the main component.

[0019] Furthermore, the high-elasticity and high-stability medical catheter includes an infusion, nursing or implantation medical catheter.

[0020] The beneficial effects of the present invention are: 1. The raw material ratio between the elastomer and the high-polymerization plasticizer, stabilizer and processing aid in the high-elasticity and high-stability PVC granules of the present invention is reasonable, and has a synergistic effect. At the same time, it has the effects of synergistic plasticization, synergistic stabilization and optimized dimensional stability, which complement each other and work together to optimize the performance of the material. At the same time, the lubricating processing aid and the lubricant also have a synergistic effect, which is beneficial to the secondary processing of the product, and can increase the melt fluidity of the granules, so as to increase the traction speed and thus improve the production capacity, save energy and reduce consumption.

[0021] 2. In the high-elasticity and high-stability PVC granules of the present invention, an environmentally friendly non-phthalate plasticizer is used to replace the phthalate plasticizer, which greatly improves the elasticity of PVC and makes it reach the level of elastomers. Its unique high resilience and high flexibility can better adapt to infusion, nursing or implantation of medical catheters. At the same time, it overcomes the harm of the phthalate plasticizer in the existing PVC granules to the human body, eliminates the possibility of thrombosis caused by the migration of the phthalate plasticizer in the PVC granules, and avoids the possibility that the phthalate plasticizer may be a carcinogen and cause harm to the human body.

[0022] 3. The pre-plasticization of the high-elasticity and high-stability PVC granules in the present invention adopts the process conditions of adding liquid in batches, which is conducive to the full absorption of the liquid in the raw material, and the plasticization effect is better, so that the secondary processing temperature of the product is low, and energy saving and consumption reduction are reduced; in addition, color powder can also be added as needed during processing to obtain products of different colors. The use of the liquid stirring tank in the present invention can also avoid uneven dispersion of color powder caused by suspension phenomenon, and the appearance color consistency of the obtained product is better.

[0023] 4. The reasonable combination of pre-plasticization process conditions and granulation conditions of the high-elasticity and high-stability PVC granules in the present invention helps to further improve the plasticization effect and can effectively solve the appearance problems such as black spots, crystal points, bubbles, etc. on the surface of the pipe product.

[0024] 5. The high-elasticity and high-stability PVC granules of the present invention have excellent thermal stability, which can improve the production stability and continuity during secondary processing, thereby reducing the problems of head filter blockage and traction speed reduction caused by aging or coke, thereby improving production efficiency and increasing production capacity.

[0025] 6. The high-elasticity and high-stability PVC granules of the present invention also have excellent elasticity and tensile toughness, so that the processed products are not prone to appearance defects such as wrinkles and bends during storage, and can reduce the problem of poor liquid flow caused by product deformation due to mis-pressing by users during product application.

[0026] 7. The high-elasticity and high-stability medical catheter tube body of the present invention has a low glass transition temperature of the material, which achieves a cold-resistant effect, is conducive to the transportation of the product under cold conditions, and avoids losses caused by brittle fracture. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In order to more clearly illustrate the technical solution of the present invention, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0028] Attached Figure 1 This is a product diagram of high-elasticity and high-stability PVC granules in the embodiment; Attached Figure 2 It is a test diagram of the bending performance of the medical catheter tube body in the embodiment and the comparative example; Attached Figure 3 The thermal stability test results of the pellet products in the embodiments and comparative examples are shown in FIG. Attached Figure 4 1 is an appearance diagram of the medical catheter body in the embodiment and the comparative example. DETAILED DESCRIPTION

[0029] The technical solutions in the embodiments of the present invention will be described clearly and completely below in conjunction with the accompanying drawings. The embodiments mentioned are all implemented on the premise of the technical solutions of the present invention, and detailed implementation processes are given, but it should be stated that the protection scope of the present invention is not limited to the following embodiments.

[0030] The main raw materials of the high-elasticity and high-stability PVC granules in the present invention include: 100 parts of PVC resin powder, 50-60 parts of plasticizer, 5-10 parts of epoxy soybean oil, 0.6-1.5 parts of composite heat stabilizer, 0.4-6 parts of elastomer, 0.4-0.8 parts of processing aid, 0.1-0.4 parts of lubricant; the raw materials are measured by weight. First, the solid raw materials are mixed and added to a high mixing pot, and then the liquid raw materials are mixed and mixed with the solid raw materials in two batches, and the mixing process of the high mixing pot is controlled to obtain pre-plasticized raw materials; finally, the pre-plasticized raw materials are melt-extruded and granulated by an extruder. The obtained high-elasticity and high-stability PVC granules are melt-extruded to prepare a high-elasticity and high-stability medical catheter body, and the tube body can be assembled to obtain a medical catheter product, and the medical catheter product includes infusion, nursing or implantation medical catheters.

[0031] The raw materials used in the embodiments and comparative examples are described as follows, but are not limited to these raw materials. The raw materials can be directly commercially available raw materials: resin powder: PVC resin powder, with an average degree of polymerization of 2500; elastomer: powdered PVC elastomer, liquid nitrile rubber, liquid chlorinated polyethylene; composite heat stabilizer (main stabilizer and auxiliary stabilizer are compounded in proportion): main stabilizer zinc stearate and calcium stearate; auxiliary stabilizer: diisooctyl phosphite; processing aid: formed by compounding acrylic copolymers ACR of different molecular weights, and the present invention uses three models of PA-40 (high molecular weight), PA-20 (medium molecular weight), and PA-101 (low molecular weight) of Japan Kaneka Chemical Industry Co., Ltd. for compounding; lubricant: oxidized polyethylene wax, stearic acid, benzyl methyl silicone oil; plasticizer: trioctyl trimellitate (TOTM), dioctyl terephthalate (DOTP), dioctyl adipate (DOA), and dioctyl phthalate (DOP).

[0032] Example 1 Preparation of high elasticity and high stability PVC granules Pre-plasticization of raw materials: weigh solid raw materials: 100 parts of polyvinyl chloride resin, 0.6 parts of composite heat stabilizer (including 0.06 parts of zinc stearate and 0.18 parts of calcium stearate), 2 parts of powdered PVC elastomer, 0.4 parts of processing aid (including 0.1 parts of PA-101 and 0.3 parts of PA-40), 0.1 parts of lubricant oxidized polyethylene wax, and pour the weighed raw materials into a high mixing pot; then weigh liquid additives: 60 parts of DOTP, 5 parts of epoxy soybean oil, 0.36 parts of diisooctyl phosphite, and pour the weighed liquid additives into a liquid stirring tank. Start the high-speed mixing pot switch, and set the mixing conditions to: low-speed stirring at a stirring speed of 200rpm / min. When the material temperature rises to 50℃, start adding liquid at a rate of 50%. When the temperature returns to 80℃, add the remaining 50% of the liquid. Continue stirring until the temperature rises to 85℃, then switch to high-speed stirring at a high-speed mixing speed of 700rpm / min. When the material temperature rises to 120℃, discharge the material. Set the cooling temperature to 45℃ and set aside.

[0033] Granulation: The pre-plasticized raw materials are melted and extruded through an extruder, and granulated to obtain high-elasticity and high-stability PVC granules. The granulation conditions of the extruder are main engine speed 260±20rpm / min, feeding speed 160±20rpm / min, pelletizing speed 250±20rpm / min, and extruder temperature conditions of 80-120℃.

[0034] Preparation of high elasticity and high stability medical catheter tube The high-elasticity and high-stability PVC pellets are subjected to secondary melt extrusion molding to obtain a high-elasticity and high-stability medical catheter tube body. The operating conditions of the extruder are a main engine speed of 55±5rpm / min, a traction speed of 60±5rpm / min, and an extruder temperature of 135-155℃.

[0035] Example 2 Preparation of high elasticity and high stability PVC granules Pre-plasticization of raw materials: weigh solid raw materials: 100 parts of polyvinyl chloride resin, 0.8 parts of composite heat stabilizer (including 0.08 parts of zinc stearate and 0.24 parts of calcium stearate), 3 parts of powdered PVC elastomer, 0.6 parts of processing aid (including 0.15 parts of PA-101 and 0.45 parts of PA-20), 0.2 parts of lubricant stearic acid, and pour the weighed raw materials into a high mixing pot; then weigh liquid additives: 56 parts of DOTP, 6 parts of epoxy soybean oil, 0.48 parts of diisooctyl phosphite, and pour the weighed liquid additives into a liquid stirring tank. Start the high-speed mixing pot switch, and set the mixing conditions to: low-speed stirring at a stirring speed of 250rpm / min. When the material temperature rises to 60℃, start adding liquid at a rate of 60%. When the temperature returns to 80℃, add the remaining 40% of liquid. Continue stirring until the temperature rises to 100℃, then switch to high-speed stirring at a high-speed mixing speed of 750rpm / min. When the material temperature rises to 125℃, discharge the material. Set the cooling temperature to 50℃ and set aside.

[0036] Granulation: The pre-plasticized PVC raw material is melted and extruded through an extruder, and granulated to obtain high-elasticity and high-stability PVC granules. The granulation conditions of the extruder are main engine speed 260±20rpm / min, feeding speed 160±20rpm / min, pelletizing speed 250±20rpm / min, and extruder temperature conditions of 80-120℃.

[0037] Preparation of high elasticity and high stability medical catheter tube The high-elasticity and high-stability PVC pellets are subjected to secondary melt extrusion molding to obtain a high-elasticity and high-stability medical catheter tube body. The operating conditions of the extruder are a main engine speed of 55±5rpm / min, a traction speed of 60±5rpm / min, and an extruder temperature of 135-155℃.

[0038] Embodiment 3: Preparation of high elasticity and high stability PVC granules Pre-plasticization of raw materials: weigh solid raw materials: 100 parts of polyvinyl chloride resin, 1.0 parts of composite heat stabilizer (including 0.1 parts of zinc stearate and 0.3 parts of calcium stearate), 0.8 parts of processing aids (including 0.16 parts of PA-101, 0.32 parts of PA-20 and 0.32 parts of PA-40), 0.1 parts of lubricant oxidized polyethylene wax and 0.2 parts of lubricant stearic acid, and pour the weighed raw materials into a high mixing pot; then weigh liquid additives: 57 parts of DOA, 7 parts of epoxy soybean oil, 0.6 parts of diisooctyl phosphite and 6 parts of liquid chlorinated polyethylene (elastomer), and pour the weighed liquid additives into a liquid stirring tank. Start the high-speed mixing pot switch, and set the mixing conditions to: low-speed stirring at a stirring speed of 300 rpm / min. When the material temperature rises to 80°C, start adding liquid at a rate of 70%. When the temperature returns to 75°C, add the remaining 30% of liquid. Continue stirring until the temperature rises to 110°C, then switch to high-speed stirring at a speed of 800 rpm / min. When the material temperature rises to 135°C, discharge the material. Set the cooling temperature to 60°C and set aside.

[0039] Granulation: The pre-plasticized PVC raw material is melted and extruded through an extruder, and granulated to obtain high-elasticity and high-stability PVC granules. The granulation conditions of the extruder are main engine speed 260±20rpm / min, feeding speed 160±20rpm / min, pelletizing speed 250±20rpm / min, and extruder temperature conditions of 80-120℃.

[0040] Preparation of high elasticity and high stability medical catheter tube The high-elasticity and high-stability PVC pellets are subjected to secondary melt extrusion molding to obtain a high-elasticity and high-stability medical catheter tube body. The operating conditions of the extruder are a main engine speed of 55±5rpm / min, a traction speed of 60±5rpm / min, and an extruder temperature of 135-155℃.

[0041] Embodiment 4: Preparation of high elasticity and high stability PVC granules Pre-plasticization of raw materials: weigh solid raw materials: 100 parts of polyvinyl chloride resin, 1.2 parts of composite heat stabilizer (including 0.12 parts of zinc stearate and 0.36 parts of calcium stearate), 0.5 parts of processing aid (including 0.125 parts of PA-101 and 0.375 parts of PA-40), 0.2 parts of lubricant oxidized polyethylene wax, 0.2 parts of lubricant stearic acid, and pour the weighed raw materials into a high mixing pot; then weigh liquid additives: 50 parts of TOTM, 8 parts of epoxy soybean oil, 0.72 parts of diisooctyl phosphite, 4 parts of liquid chlorinated polyethylene, and pour the weighed liquid additives into a liquid stirring tank. Start the high-speed mixing pot switch, and set the mixing conditions to: low-speed stirring at a stirring speed of 200rpm / min. When the material temperature rises to 80℃, start adding liquid, and the addition amount is 80%. When the temperature returns to 75℃, add the remaining 20% ​​of liquid, and continue stirring until the temperature rises to 100℃, then switch to high-speed stirring, and the high-speed mixing speed is 850rpm / min. When the material temperature rises to 130℃, discharge the material, and set the cooling temperature to 65℃ for standby use.

[0042] Granulation: The pre-plasticized PVC raw material is melted and extruded through an extruder, and granulated to obtain high-elasticity and high-stability PVC granules. The granulation conditions of the extruder are main engine speed 260±20rpm / min, feeding speed 160±20rpm / min, pelletizing speed 250±20rpm / min, and extruder temperature conditions of 80-120℃.

[0043] Preparation of high elasticity and high stability medical catheter tube The high-elasticity and high-stability PVC pellets are subjected to secondary melt extrusion molding to obtain a high-elasticity and high-stability medical catheter tube body. The operating conditions of the extruder are a main engine speed of 55±5rpm / min, a traction speed of 60±5rpm / min, and an extruder temperature of 135-155℃.

[0044] Embodiment 5: Preparation of high elasticity and high stability PVC granules Pre-plasticization of raw materials: weigh solid raw materials: 100 parts of polyvinyl chloride resin, 1.4 parts of composite heat stabilizer (including 0.14 parts of zinc stearate and 0.42 parts of calcium stearate), 0.7 parts of processing aids (including 0.14 parts of PA-101, 0.28 parts of PA-20 and 0.28 parts of PA-40), 0.2 parts of lubricant oxidized polyethylene wax, and pour the weighed raw materials into a high mixing pot; then weigh liquid additives: 56 parts of TOTM, 9 parts of epoxy soybean oil, 0.84 parts of diisooctyl phosphite, and 0.4 parts of liquid nitrile rubber, and pour the weighed liquid additives into a liquid stirring tank. Start the high-speed mixing pot switch, and set the mixing conditions to: low-speed stirring at a stirring speed of 300rpm / min. When the material temperature rises to 50℃, start adding liquid at a rate of 50%. When the temperature returns to 80℃, add the remaining 50% of the liquid. Continue stirring until the temperature rises to 85℃, then switch to high-speed stirring at a speed of 900rpm / min. When the material temperature rises to 120℃, discharge the material. Set the cooling temperature to 45℃ and set aside.

[0045] Granulation: The pre-plasticized PVC raw material is melted and extruded through an extruder, and granulated to obtain high-elasticity and high-stability PVC granules. The granulation conditions of the extruder are main engine speed 260±20rpm / min, feeding speed 160±20rpm / min, pelletizing speed 250±20rpm / min, and extruder temperature conditions of 80-120℃.

[0046] Preparation of high elasticity and high stability medical catheter tube The high-elasticity and high-stability PVC pellets are subjected to secondary melt extrusion molding to obtain a high-elasticity and high-stability medical catheter tube body. The operating conditions of the extruder are a main engine speed of 55±5rpm / min, a traction speed of 60±5rpm / min, and an extruder temperature of 135-155℃.

[0047] Embodiment 6: Preparation of high elasticity and high stability PVC granules Pre-plasticization of raw materials: weigh solid raw materials: 100 parts of polyvinyl chloride resin, 1.5 parts of composite heat stabilizer (including 0.15 parts of zinc stearate and 0.45 parts of calcium stearate), 4 parts of powdered PVC elastomer, 0.4 parts of processing aid (including 0.1 parts of PA-101 and 0.3 parts of PA-20), 0.1 parts of lubricant oxidized polyethylene wax, and pour the weighed raw materials into a high mixing pot; then weigh liquid additives: 52 parts of TOTM, 10 parts of epoxy soybean oil, and 0.9 parts of diisooctyl phosphite, and pour the weighed liquid additives into a liquid stirring tank. Start the high-speed mixing pot switch, and set the mixing conditions to: low-speed stirring at a stirring speed of 200 rpm / min. When the material temperature rises to 60°C, start adding liquid at a rate of 60%. When the temperature returns to 80°C, add the remaining 40% of liquid. Continue stirring until the temperature rises to 100°C, then switch to high-speed stirring at a high-speed mixing speed of 900 rpm / min. When the material temperature rises to 125°C, discharge the material. Set the cooling temperature to 50°C and set aside.

[0048] Granulation: The pre-plasticized PVC raw material is melted and extruded through an extruder, and granulated to obtain high-elasticity and high-stability PVC granules. The granulation conditions of the extruder are main engine speed 260±20rpm / min, feeding speed 160±20rpm / min, pelletizing speed 250±20rpm / min, and extruder temperature conditions of 80-120℃.

[0049] Preparation of high elasticity and high stability medical catheter tube The high-elasticity and high-stability PVC pellets are subjected to secondary melt extrusion molding to obtain a high-elasticity and high-stability medical catheter tube body. The operating conditions of the extruder are a main engine speed of 55±5rpm / min, a traction speed of 60±5rpm / min, and an extruder temperature of 135-155℃.

[0050] Embodiment 7: Preparation of high elasticity and high stability PVC granules Pre-plasticization of raw materials: weigh solid raw materials: 100 parts of polyvinyl chloride resin, 1.4 parts of composite heat stabilizer (including 0.14 parts of zinc stearate and 0.42 parts of calcium stearate), 5 parts of powdered PVC elastomer, 0.6 parts of processing aid (including 0.15 parts of PA-101 and 0.45 parts of PA-40), 0.2 parts of lubricant stearic acid, and pour the weighed raw materials into a high mixing pot; then weigh liquid additives: 55 parts of TOTM, 9 parts of epoxy soybean oil, 0.84 parts of diisooctyl phosphite, and pour the weighed liquid additives into a liquid stirring tank. Start the high-speed mixing pot switch, and set the mixing conditions to: low-speed stirring at a stirring speed of 300rpm / min. When the material temperature rises to 60℃, start adding liquid at a rate of 60%. When the temperature returns to 80℃, add the remaining 40% of liquid. Continue stirring until the temperature rises to 100℃, then switch to high-speed stirring at a speed of 800rpm / min. When the material temperature rises to 125℃, discharge the material. Set the cooling temperature to 50℃ and set aside.

[0051] Granulation: The pre-plasticized PVC raw material is melted and extruded through an extruder, and granulated to obtain high-elasticity and high-stability PVC granules. The granulation conditions of the extruder are main engine speed 260±20rpm / min, feeding speed 160±20rpm / min, pelletizing speed 250±20rpm / min, and extruder temperature conditions of 80-120℃.

[0052] Preparation of high elasticity and high stability medical catheter tube The high-elasticity and high-stability PVC pellets are subjected to secondary melt extrusion molding to obtain a high-elasticity and high-stability medical catheter tube body. The operating conditions of the extruder are a main engine speed of 55±5rpm / min, a traction speed of 60±5rpm / min, and an extruder temperature of 135-155℃.

[0053] Embodiment 8: Preparation of high elasticity and high stability PVC granules Pre-plasticization of raw materials: weigh solid raw materials: 100 parts of polyvinyl chloride resin, 1.2 parts of composite heat stabilizer (including 0.12 parts of zinc stearate and 0.36 parts of calcium stearate), 0.8 parts of processing aid (including 0.16 parts of PA-101, 0.32 parts of PA-20 and 0.32 parts of PA-40), 0.1 parts of lubricant benzyl silicone oil and 0.2 parts of lubricant oxidized polyethylene wax, and pour the weighed raw materials into a high mixing pot; then weigh liquid additives: 55 parts of TOTM, 8 parts of epoxy soybean oil, 0.72 parts of diisooctyl phosphite and 0.6 parts of liquid nitrile rubber, and pour the weighed liquid additives into a liquid stirring tank. Start the high-speed mixing pot switch, and set the mixing conditions to: low-speed stirring at a stirring speed of 250rpm / min. When the material temperature rises to 80℃, start adding liquid at a rate of 70%. When the temperature returns to 75℃, add the remaining 30% of liquid. Continue stirring until the temperature rises to 110℃, then switch to high-speed stirring at a speed of 800rpm / min. When the material temperature rises to 135℃, discharge the material. Set the cooling temperature to 60℃ and set aside.

[0054] Granulation: The pre-plasticized PVC raw material is melted and extruded through an extruder, and granulated to obtain high-elasticity and high-stability PVC granules. The granulation conditions of the extruder are main engine speed 260±20rpm / min, feeding speed 160±20rpm / min, pelletizing speed 250±20rpm / min, and extruder temperature conditions of 80-120℃.

[0055] Preparation of high elasticity and high stability medical catheter tube The high-elasticity and high-stability PVC pellets are subjected to secondary melt extrusion molding to obtain a high-elasticity and high-stability medical catheter tube body. The operating conditions of the extruder are a main engine speed of 55±5rpm / min, a traction speed of 60±5rpm / min, and an extruder temperature of 135-155℃.

[0056] Embodiment 9: Preparation of high elasticity and high stability PVC granules Pre-plasticization of raw materials: weigh solid raw materials: 100 parts of polyvinyl chloride resin, 1.0 parts of composite heat stabilizer (including 0.1 parts of zinc stearate and 0.3 parts of calcium stearate), 0.7 parts of processing aid (including 0.175 parts of PA-101 and 0.525 parts of PA-20), 0.2 parts of lubricant oxidized polyethylene wax, 0.2 parts of lubricant stearic acid, and pour the weighed raw materials into a high mixing pot; then weigh liquid additives: 55 parts of TOTM, 7 parts of epoxy soybean oil, 0.6 parts of diisooctyl phosphite, and 0.4 parts of liquid nitrile rubber, and pour the weighed liquid additives into a liquid stirring tank. Start the high-speed mixing pot switch, and set the mixing conditions to: low-speed stirring at a stirring speed of 200rpm / min. When the material temperature rises to 80℃, start adding liquid, and the addition amount is 80%. When the temperature returns to 75℃, add the remaining 20% ​​of liquid, and continue stirring until the temperature rises to 100℃, then switch to high-speed stirring, and the high-speed mixing speed is 800rpm / min. When the material temperature rises to 130℃, discharge the material, and set the cooling temperature to 65℃ for standby use.

[0057] Granulation: The pre-plasticized PVC raw material is melted and extruded through an extruder, and granulated to obtain high-elasticity and high-stability PVC granules. The granulation conditions of the extruder are main engine speed 260±20rpm / min, feeding speed 160±20rpm / min, pelletizing speed 250±20rpm / min, and extruder temperature conditions of 80-120℃.

[0058] Preparation of high elasticity and high stability medical catheter tube The high-elasticity and high-stability PVC pellets are subjected to secondary melt extrusion molding to obtain a high-elasticity and high-stability medical catheter tube body. The operating conditions of the extruder are a main engine speed of 55±5rpm / min, a traction speed of 60±5rpm / min, and an extruder temperature of 135-155℃.

[0059] Embodiment 10: Preparation of high elasticity and high stability PVC granules Pre-plasticization of raw materials: weigh solid raw materials: 100 parts of polyvinyl chloride resin, 0.6 parts of composite heat stabilizer (including 0.06 parts of zinc stearate and 0.18 parts of calcium stearate), 0.5 parts of processing aids (including 0.125 parts of PA-101 and 0.375 parts of PA-40), 0.2 parts of lubricant oxidized polyethylene wax, and pour the weighed raw materials into a high mixing pot; then weigh liquid additives: 58 parts of DOA, 5 parts of epoxy soybean oil, 0.36 parts of diisooctyl phosphite, and 4 parts of liquid chlorinated polyethylene, and pour the weighed liquid additives into a liquid stirring tank. Start the high-speed mixing pot switch, and set the mixing conditions to: low-speed stirring at a stirring speed of 250rpm / min. When the material temperature rises to 50℃, start adding liquid at a rate of 50%. When the temperature returns to 80℃, add the remaining 50% of the liquid. Continue stirring until the temperature rises to 85℃, then switch to high-speed stirring at a speed of 700rpm / min. When the material temperature rises to 120℃, discharge the material. Set the cooling temperature to 45℃ and set aside.

[0060] Granulation: The pre-plasticized PVC raw material is melted and extruded through an extruder, and granulated to obtain high-elasticity and high-stability PVC granules. The granulation conditions of the extruder are main engine speed 260±20rpm / min, feeding speed 160±20rpm / min, pelletizing speed 250±20rpm / min, and extruder temperature conditions of 80-120℃.

[0061] Preparation of high elasticity and high stability medical catheter tube The high-elasticity and high-stability PVC pellets are subjected to secondary melt extrusion molding to obtain a high-elasticity and high-stability medical catheter tube body. The operating conditions of the extruder are a main engine speed of 55±5rpm / min, a traction speed of 60±5rpm / min, and an extruder temperature of 135-155℃.

[0062] Comparative Example 1 Pre-plasticization of PVC pellets for ordinary pipe bodies, weigh solid raw materials: 100 parts of polyvinyl chloride resin, 0.2 parts of zinc stearate, 0.4 parts of calcium stearate, 0.4 parts of PA-20, 0.2 parts of lubricant oxidized polyethylene wax, pour the weighed raw materials into a high-mixing pot; then weigh liquid additives: 55 parts of dioctyl phthalate (DOP), 5 parts of epoxy soybean oil, pour the weighed liquid additives into the liquid mixing tank. Start the high-mixing pot switch, and set the mixing conditions to: low-speed stirring, stirring speed is 200rpm / min, wait for the material temperature to rise to 60℃, start adding liquid, add liquid once, continue stirring until the temperature rises to 110℃, turn to high-speed stirring, high-speed mixing speed is 700rpm / min, wait for the material temperature to rise to 122℃, discharge, cool the temperature to 45℃, and set it aside.

[0063] Preparation of PVC pellets for pipe body: melt and extrude the pre-plasticized PVC raw materials through an extruder, granulate and shape them to obtain PVC pellets for pipe body. The granulation conditions of the extruder are main machine speed 260±20rpm / min, feeding speed 160±20rpm / min, pelletizing speed 250±20rpm / min, and extruder temperature condition 90-125℃.

[0064] The PVC pipe body is prepared by melting and extruding the high-elasticity and high-stability PVC pellets for the second time to obtain the PVC pipe body. The operating conditions of the extruder are the main engine speed of 55±5rpm / min, the traction speed of 60±5rpm / min, and the extruder temperature of 140-165℃.

[0065] Comparative Example 2 Pre-plasticization of PVC pellets for the stability pipe body, weigh solid raw materials: 100 parts of polyvinyl chloride resin, 0.7 parts of composite heat stabilizer (including 0.07 parts of zinc stearate and 0.21 parts of calcium stearate), 0.4 parts of processing aids (including 0.08 parts of PA-101, 0.16 parts of PA-20, and 0.16 parts of PA-40), 0.1 parts of lubricant oxidized polyethylene wax, and pour the weighed raw materials into a high mixing pot; then weigh liquid additives: 60 parts of dioctyl phthalate (DOP), 6 parts of epoxy soybean oil, and 0.42 parts of diisooctyl phosphite, and pour the weighed liquid additives into a liquid stirring tank. Start the high-speed mixing pot switch and set the mixing conditions to: low-speed stirring at a stirring speed of 250rpm / min. When the material temperature rises to 60℃, start adding liquid, add liquid once, and continue stirring until the temperature rises to 110℃, then switch to high-speed stirring at a high-speed mixing speed of 800rpm / min. When the material temperature rises to 122℃, discharge the material, set the cooling temperature to 45℃, and set aside.

[0066] The preparation of PVC pellets for the pipe body is to melt and extrude the pre-plasticized PVC raw materials through an extruder, granulate and shape them to obtain high-elasticity and high-stability PVC pellets. The granulation conditions of the extruder are the main engine speed of 260±20rpm / min, the feeding speed of 160±20rpm / min, the pelletizing speed of 250±20rpm / min, and the extruder temperature of 100-130℃.

[0067] Preparation of stable PVC pipe body: The stable pipe body is formed by secondary melt extrusion of PVC pellets to obtain a high elasticity and high stability medical catheter pipe body. The operating conditions of the extruder are main machine speed 55±5rpm / min, traction speed 60±5rpm / min, and extruder temperature condition 140-165℃.

[0068] Comparative Example 3 Pre-plasticization of PVC pellets for elastic tubes, weigh solid raw materials: 100 parts of polyvinyl chloride resin, 0.12 parts of zinc stearate, 0.36 parts of calcium stearate, 0.4 parts of PA-40, 0.2 parts of lubricant oxidized polyethylene wax, 3 parts of powdered PVC elastomer, pour the weighed raw materials into a high-mixing pot; then weigh liquid additives: 60 parts of dioctyl phthalate (DOP), 5 parts of epoxy soybean oil, 0.5 parts of diisooctyl phosphite, pour the weighed liquid additives into a liquid mixing tank. Start the high-mixing pot switch, and set the mixing conditions to: low-speed stirring, stirring speed of 300rpm / min, start adding liquid when the material temperature rises to 60℃, add liquid once, continue stirring until the temperature rises to 110℃, turn to high-speed stirring, high-speed mixing speed is 900rpm / min, when the material temperature rises to 122℃, discharge, cooling temperature is set to 45℃, and set aside.

[0069] Preparation of PVC pellets for elastic tube body: melt and extrude the pre-plasticized PVC raw material through an extruder, granulate and shape, and obtain PVC pellets for elastic tube body. The granulation conditions of the extruder are main engine speed 260±20rpm / min, feeding speed 160±20rpm / min, pelletizing speed 250±20rpm / min, and extruder temperature condition 80-120℃.

[0070] The PVC pipe body is prepared by melting and extruding the PVC pellets for the pipe body twice to obtain an elastic PVC pipe body. The operating conditions of the extruder are a main engine speed of 55±5rpm / min, a traction speed of 60±5rpm / min, and an extruder temperature of 135-155°C.

[0071] Implementation effect analysis The granular material performance testing methods in the embodiments and comparative examples are as follows: (1) The UV absorbance was tested according to the chemical analysis method in GB / T 14233.1-2008. The pellets were pressed into a 300 cm 2 The sample is evenly cut into 1cm 2 Prepare the test solution after testing the test samples to test the precipitation of additives in the material; (2) The tensile properties were tested according to the GB / T 1040.2-2006 method. The pellets were made into standard specimens with a thickness of 2 mm. (3) The rebound performance is tested by preparing samples according to the method of GB / T 1681-2009, and the elasticity of the standard sample is tested; (4) Melt flow rate (MFR) is measured on pellets in accordance with GB / T 3682.1-2018 Plastics - Determination of melt mass flow rate (MFR) and melt volume flow rate (MVR) of thermoplastics - Part 1: Standard method.

[0072] (5) Thermal stability test: The thermal stability of the test specimens was tested at 180°C in accordance with the method of GB / T 2917.1-2002.

[0073] The test results are shown in Table 1 below: It can be seen from the data in Table 1 that the high-elasticity and high-stability PVC pellets (such as Figure 1 The granular product shown in the figure has excellent performance. Its average UV absorbance is 0.12, which is much lower than the 0.17 of the comparative example, indicating that the probability of the precipitation of additives in the material has been greatly reduced, and the contact between medical devices and the human body is safer; the average elongation at break is 433.69%, which is much higher than the 272.43% of the comparative example, and the average rebound rate is 29.56%, which is much higher than the 17.56% of the comparative example, which fully demonstrates that the material has excellent elasticity and tensile toughness. Figure 2 It can be seen that the medical catheter tube body prepared as the raw material is not prone to appearance defects such as wrinkles and bends during storage, and during product application, it can reduce the problem of poor liquid flow caused by product deformation due to mis-pressing by users.

[0074] It can be seen from the melt index data in Table 1 that the melt index of the high-elasticity and high-stability PVC granules in the present invention is greatly improved, and the average melt index is 4.79 g / 10min, which is much higher than 2.46 g / 10min of the comparative example. The elastomer in the high-elasticity and high-stability PVC granules of the present invention has a synergistic effect with the plasticizer with a high degree of polymerization, the stabilizer, and the processing aid, and has the effects of synergistic plasticization, synergistic stabilization, and optimized dimensional stability, which complement each other and work together to optimize the performance of the material. At the same time, the lubricating processing aid and the lubricant also have a synergistic effect, which is beneficial to the secondary processing of the product, and can increase the melt fluidity of the granules, so as to increase the traction speed and thus improve the production capacity, save energy and reduce consumption.

[0075] Combining the thermal stability data in Table 1 and Figure 3 The test results show that the sample of the comparative example becomes obviously darker in color after about 1 hour, while the high-elasticity and high-stability PVC pellets of the present invention have excellent thermal stability, which can improve the production stability and continuity during secondary processing, thereby reducing the problems of head filter blockage and traction speed reduction caused by aging or coke, thereby improving production efficiency and increasing production capacity; Figure 4 As shown, the reasonable combination of pre-plasticizing process conditions and granulation conditions of the high-elasticity and high-stability PVC granules in the present invention helps to further improve the plasticizing effect and can effectively solve the appearance problems such as black spots, crystal points, bubbles, etc. on the surface of the pipe product.

[0076] The above description of the disclosed embodiments enables those skilled in the art to implement or use the present invention. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but rather to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A high-elasticity and high-stability PVC granules, characterized in that: The main raw materials include: 100 parts of PVC resin powder, 50-60 parts of plasticizer, 5-10 parts of epoxy soybean oil, 0.6-1.5 parts of composite heat stabilizer, 0.4-6 parts of elastomer, 0.4-0.8 parts of processing aid, 0.1-0.4 parts of lubricant; the raw materials are calculated by weight.

2. The high-elasticity and high-stability PVC granules according to claim 1, characterized in that: The composite heat stabilizer comprises 5-7 parts of a main stabilizer and 3-5 parts of an auxiliary stabilizer; the main stabilizer is composed of zinc stearate and calcium stearate in a mass ratio of 1:1-5, and the auxiliary stabilizer comprises diisooctyl phosphite; the components are measured in parts by weight; the elastomer comprises chlorinated polyethylene, PVC elastomer or nitrile rubber.

3. The high-elasticity and high-stability PVC granules according to claim 1, characterized in that: The processing aid is formed by compounding acrylic acid ester copolymers with different molecular weights.

4. The high-elasticity and high-stability PVC granules according to claim 1, characterized in that: The average polymerization degree of the PVC resin powder is 1800-2500; the plasticizer is an environmentally friendly non-phthalic plasticizer, including diisooctyl terephthalate, dioctyl adipate or trioctyl trimellitate; the lubricant includes any one or more of oxidized polyethylene wax, stearic acid and benzyl silicone oil.

5. A method for preparing high-elasticity and high-stability PVC granules according to any one of claims 1 to 4, characterized in that: The following steps are involved: S1, firstly mix the solid raw materials, then mix the liquid raw materials and then mix them with the solid raw materials in batches, control the mixing process, and obtain pre-plasticized raw materials; S2, melt-extrude the pre-plasticized raw materials through an extruder, and granulate them to obtain the pre-plasticized raw materials.

6. The preparation method according to claim 5, characterized in that: The mixing process described in S1 includes: S11, adding the solid raw material into a high mixing pot, setting the mixing speed to 200-300rpm / min, and adding 50%-80% of the liquid raw material after the solid raw material is heated to 50-80°C; S12, after the temperature rises to 65-85°C, adding the remaining liquid raw material, continuing to stir and heating to 90-110°C, setting the mixing speed to 700-900rpm / min, and after the material temperature rises to 120-135°C, discharging the material, and finally cooling it to 45-65°C.

7. The preparation method according to claim 5, characterized in that: The granulation conditions of the extruder in S2 are: main engine speed 260±20rpm / min, feeding speed 160±20rpm / min, pelletizing speed 250±20rpm / min, and extrusion temperature 80-120°C.

8. Use of the high-elasticity and high-stability PVC granules according to any one of claims 1 to 4 in the preparation of medical catheter bodies or catheters.

9. A high-elasticity and high-stability medical catheter body, characterized in that: The high-elasticity and high-stability PVC pellets according to any one of claims 1 to 4 are used as raw materials and prepared by melt extrusion molding. The extrusion molding conditions are: main machine speed 55±5rpm / min, traction speed 60±5rpm / min, and extruder temperature condition 135-155℃.

10. A high-elasticity and high-stability medical catheter, characterized in that: The high-elasticity and high-stability medical catheter tube body as claimed in claim 9 is assembled as the main component.

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