A high temperature resistant and easily broken polystyrene composite material and its preparation and application

Abstract

The present invention relates to a high temperature resistant and easily broken polystyrene composite material and its preparation and application, the components include: polystyrene, styrene-butadiene copolymer, styrene-maleic anhydride copolymer. The present invention has a high Vicat softening point temperature, is not easily deformed by heat, and the sampling rod made of the composite material of the present invention is suitable for sterilization by moist heat sterilization; at the same time, the sampling rod has good easy-to-break performance, and can be broken by bending to a certain angle, is not too brittle or too tough, and has good application prospects.

Description

Technical Field

[0001] The invention belongs to the field of plastic processing, and particularly relates to a high-temperature resistant and easily-fragile polystyrene composite material and a preparation method and application thereof. Background Art

[0002] ABS and HIPS materials are widely used in disposable sampling rod products for COVID-19 nucleic acid testing due to their easy processing, good dimensional stability and high cost performance. However, due to their high impact strength, good toughness and difficulty in breaking, ABS and HIPS materials make it difficult to break the sampling rod, which seriously affects the sampling efficiency and may cause leakage and contamination; however, the sampling rod cannot be too brittle, because it is too easy to break, which may cause the sampling rod to break easily during use. On the other hand, moist heat sterilization (saturated water vapor at 100°C or above) is the most widely used sterilization method among thermal sterilization methods due to its strong sterilization ability and high cost performance. However, due to their low heat deformation temperature, ABS and HIPS materials are easy to deform under high temperature conditions, making it impossible to use moist heat sterilization for sterilization and disinfection. Summary of the invention

[0003] In view of the above technical defects, the technical problem to be solved by the present invention is to provide a high-temperature resistant and easily broken polystyrene composite material and its preparation and application.

[0004] The polystyrene composite material of the present invention comprises the following components by weight:

[0005] Polystyrene 100 parts;

[0006] 15-35 parts of styrene-butadiene copolymer;

[0007] 30-70 parts of styrene-maleic anhydride copolymer;

[0008] The content of styrene structural components in the styrene-butadiene copolymer is 30-41 wt%, which is determined by infrared quantitative analysis;

[0009] Infrared quantitative analysis method: First, the mixture of polystyrene and polybutadiene with different known proportions was subjected to infrared analysis to establish a standard curve for the determination of styrene / butadiene component content. Then, according to the Lambert-Beer formula, the characteristic peak height of styrene (1602cm -1) The characteristic peak height of butadiene (910cm -1) The ratio of styrene SM structure component content in styrene-butadiene copolymer is calculated by proportion method.

[0010] The weight proportion of the styrene-butadiene copolymer is 15 to 35 parts. If the proportion is too small, the toughness of the composite is low, the material is too brittle, and the flexibility is poor; if the proportion is too large, the composite is too soft and will become easy to break, and the Vicat softening point temperature will also decrease. The present invention selects a styrene-butadiene copolymer with a low styrene structure content (the content of the styrene structure component is 30 to 41wt%), which has good compatibility with polystyrene and partial compatibility with styrene-maleic anhydride, and can maintain the toughness of the composite to a certain extent, and improve the easy breakability of the composite, and the flexibility is moderate; if a styrene-butadiene copolymer with a high styrene structure content is selected (the content of the styrene structure component is >41wt%), it is not only compatible with polystyrene, but also compatible with styrene-maleic anhydride copolymer, and has the function of a compatibilizer, and the composite material does not have the effect of being easy to break;

[0011] The content of maleic anhydride structural component in the styrene-maleic anhydride copolymer is 14-25 wt %.

[0012] The acid-base titration quantitative analysis method is used: first, the acid value of styrene-maleic anhydride copolymer is measured using the standard test method for acid value of styrene-maleic anhydride resin ASTM D3644-2015, and then the maleic anhydride content is calculated according to the formula:

[0013]

[0014] Calculate the content of maleic anhydride structural component in styrene-maleic anhydride copolymer.

[0015] The weight proportion of the styrene-maleic anhydride copolymer is 30-70 parts. If the proportion is too small, the composite is not easy to break and the Vicat softening point temperature is too low; if the proportion is too large, although the Vicat softening point temperature is high, the bending deflection is too low and it is too easy to break. The present invention effectively reduces its compatibility with polystyrene by selecting a styrene-maleic anhydride copolymer with a high maleic anhydride structure content (the content of the maleic anhydride structure component is 14-25wt%), reduces the bending deflection of the composite, improves the easy-to-break performance, has moderate flexibility, and can effectively improve the Vicat softening point temperature of the composite; while a styrene-maleic anhydride copolymer with a low maleic anhydride structure content (the content of the maleic anhydride structure component is <14wt%) has a certain compatibility with polystyrene, and the composite thereof cannot achieve the effect of easy breaking.

[0016] According to ISO 1133-2011 standard, the melt index of the polystyrene at 200°C and 5kg is 6.5-15g / 10min. Preferably, the mass percentage of the styrene structural component in the styrene-butadiene copolymer is 35-40wt%.

[0017] When the content of the styrene structural component of the styrene-butadiene copolymer is 35-40wt%, it is helpful to toughen polystyrene and promote the phase separation of polystyrene and styrene-maleic anhydride copolymer.

[0018] Preferably, the content of maleic anhydride structural component in the styrene-maleic anhydride copolymer is 15-21 wt%.

[0019] When the content of maleic anhydride structural component of the styrene-maleic anhydride copolymer is 15-21wt%, it has partial compatibility with polystyrene and styrene-butadiene copolymer. Too low or too high content will lead to too good or too poor compatibility, which will cause the composite to be unable to bend or break too easily.

[0020] Preferably, by weight, the components include:

[0021] Polystyrene 100 parts;

[0022] 20-30 parts of styrene-butadiene copolymer;

[0023] Styrene-maleic anhydride copolymer 40-60 parts.

[0024] A method for preparing the polystyrene composite material of the present invention comprises:

[0025] The components are weighed according to the proportion, dry-mixed in a mixer, and then melt-extruded and granulated in a twin-screw extruder to obtain a polystyrene composite material.

[0026] Preferably, the dry mixing time is 3-5 minutes.

[0027] An application of the polystyrene composite material of the present invention in a disposable sampling rod, such as a sampling rod in a novel coronavirus nucleic acid test.

[0028] The present invention selects a styrene-butadiene copolymer with a low styrene structure content (the content of the styrene structure component is 30-41wt%), which is compatible with polystyrene but incompatible with a styrene-maleic anhydride copolymer, thereby maintaining the toughness of the composite to a certain extent, so that the composite is not too brittle, and effectively improves the fracture performance of the composite. However, if too much is added, the material becomes too soft and becomes too easy to break. By selecting a styrene-maleic anhydride copolymer with a high maleic anhydride structure content (the content of the maleic anhydride structure component is 14-25wt%), not only the compatibility with the polystyrene phase is reduced, the bending deflection of the composite is reduced, and the easy-to-break performance is improved, but also the Vicat softening point temperature of the composite is effectively increased, and the heat-resistant temperature of the composite is increased. By selecting polystyrene, styrene-butadiene copolymer with specific styrene structure content and styrene-maleic anhydride copolymer with specific maleic anhydride structure content, which have partial compatibility, and compounding the three substrates, a composite material with partial compatibility is obtained, which achieves a balance between high Vicat softening point temperature and bending deflection. The material is made into a sampling rod, which has the characteristics of high heat resistance and easy breakage, and is suitable for sterilization and disinfection by moist heat sterilization and large-scale new coronavirus nucleic acid sampling.

[0029] Beneficial Effects

[0030] The sampling rod made of the composite material of the present invention has a high Vicat softening point temperature, is not easily deformed by heat, and is suitable for sterilization by moist heat sterilization. At the same time, the sampling rod has good easy-to-break performance and moderate flexibility. It can be broken by bending to a certain angle. It is not too brittle, has poor flexibility, or is too tough, and has good application prospects in the new crown nucleic acid testing industry. DETAILED DESCRIPTION

[0031] The present invention will be further described below in conjunction with specific embodiments. It should be understood that these embodiments are only used to illustrate the present invention and are not intended to limit the scope of the present invention. In addition, it should be understood that after reading the content taught by the present invention, those skilled in the art can make various changes or modifications to the present invention, and these equivalent forms fall within the scope limited by the appended claims of the application equally.

[0032] 1. Source of raw materials:

[0033] Polystyrene-1PS147F, INEOS Styrolution, melt index 6.5 g / 10 min at 200 °C, 5 kg, according to ISO 1133-2011;

[0034] Polystyrene-2PS 145D, INEOS Styrolution, melt index 15 g / 10 min at 200 °C, 5 kg, according to ISO 1133-2011;

[0035] Styrene-butadiene copolymer-1SBS3537, Global Plastics, Taiwan, China, according to infrared quantitative analysis, its styrene structural component content is 35wt.%;

[0036] Styrene-butadiene copolymer-2SBS3536, Global Plastics, Taiwan, China, according to infrared quantitative analysis, its styrene structural component content is 30wt.%;

[0037] Styrene-butadiene copolymer-3SBS3542, Global Plastics, Taiwan, China, according to infrared quantitative analysis, its styrene structural component content is 40wt.%;

[0038] Styrene-butadiene copolymer-4SBS3527, Global Plastics, Taiwan, China, according to infrared quantitative analysis, its styrene structural component content is 25wt.%;

[0039] Styrene-butadiene copolymer-5SBS3545, Global Plastics, Taiwan, China, according to infrared quantitative analysis, its styrene structural component content is 45wt.%;

[0040] Styrene-maleic anhydride copolymer-1xibond 160, POLYSCOPE, according to the acid-base titration quantitative analysis method, the content of maleic anhydride structural component is 21wt.%;

[0041] Styrene-maleic anhydride copolymer-2SMA-725, Jiaxing Huawen Chemical, according to the acid-base titration quantitative analysis method, the content of maleic anhydride structural component is 25wt.%;

[0042] Styrene-maleic anhydride copolymer-3: xibond 140, POLYSCOPE, according to the acid-base titration quantitative analysis method, the content of maleic anhydride structural component is 14wt.%;

[0043] Styrene-maleic anhydride copolymer-4xibond 180, POLYSCOPE, according to the acid-base titration quantitative analysis method, the maleic anhydride structural component content is 28wt.%;

[0044] Styrene-maleic anhydride copolymer-5xibond 120, POLYSCOPE, according to the acid-base titration quantitative analysis method, the maleic anhydride structural component content is 7wt.%.

[0045] 2. Preparation methods of embodiments and comparative examples

[0046] The raw materials are weighed according to their weight proportions, and then put into a mixer with a rotation speed of about 100 rpm for dry mixing for 3-5 minutes. The mixed raw materials are then melt-extruded and granulated in a twin-screw extruder with a length-to-diameter ratio of 40:1, a temperature range of 160°C, 190°C, 190°C, 200°C, 210°C, 210°C, 220°C, 220°C, 220°C, and a rotation speed of 450 rpm to obtain a polystyrene composite material.

[0047] 3. Test standards and methods

[0048] The Vicat softening point is determined according to ISO 306-2013 and tested under B50 conditions;

[0049] The bending deflection was measured according to ISO 178-2010, test conditions: 2 mm / min, room temperature;

[0050] Heat resistance performance evaluation: Vicat softening point temperature ≥ 100℃, high heat resistance, suitable for moist heat sterilization; Vicat softening point temperature < 100℃, low heat resistance, not suitable for moist heat sterilization;

[0051] Flexibility assessment: bending deflection <10mm, poor flexibility; 10mm≤bending deflection≤30mm, moderate flexibility; 30mm<bending deflection<35mm, too good flexibility; continuous bending, unified value of 35mm.

[0052] Table 1 Proportions (parts by weight) and properties of Examples 1-10

[0053]

[0054] Table 2 Proportions (parts by weight) and properties of Comparative Examples 1-8

[0055]

[0056] It can be seen from the above test results that the special material for disposable sampling rods that is resistant to high temperatures and easy to break provided by the present invention has a bending deflection between 10 mm and 30 mm, a Vicat softening point above 100°C, and has the characteristics of moderate flexibility but not being too brittle, which effectively improves the sampling efficiency; at the same time, it has the characteristics of high temperature resistance, is not easily deformed by heat, and can be suitable for sterilization by moist heat sterilization.

[0057] Comparative Example 1 uses a styrene-butadiene copolymer with a low styrene structure content. Since the styrene structure content is too low, although it has good compatibility with polystyrene, it has poor compatibility with styrene-maleic anhydride, resulting in the composite being too brittle, too easy to break, and having poor flexibility.

[0058] Comparative Example 2 uses a styrene-butadiene copolymer with a high styrene structure content. Since the styrene structure content is too high, it has good compatibility with polystyrene and styrene-maleic anhydride copolymer, resulting in the composite being not easy to break and having good flexibility.

[0059] Comparative Example 3 uses a styrene-maleic anhydride copolymer with a high maleic anhydride structure content. Since the maleic anhydride structure content is too high, its compatibility with polystyrene and styrene-butadiene copolymer is poor, resulting in the composite being too easy to break and having poor flexibility.

[0060] In Comparative Example 4, styrene-maleic anhydride copolymer with low maleic anhydride structure content is used. Since the maleic anhydride structure content is too low, it has good compatibility with polystyrene and styrene-butadiene copolymer, resulting in the composite having too high bending deflection and not easy to break. At the same time, the Vicat softening point is too low, and it is not suitable for moist heat sterilization.

[0061] In Comparative Example 5, the amount of styrene-butadiene copolymer used is too small, the bending deflection of the composite is too small, it is too easy to break, and the flexibility is poor.

[0062] In Comparative Example 6, the amount of styrene-butadiene copolymer used is too much, and the Vicat softening point of the composite is too low, so it is not suitable for moist heat sterilization.

[0063] In Comparative Example 7, the amount of styrene-maleic anhydride copolymer used is too small, and the Vicat softening point of the composite is too low, so it is not suitable for moist heat sterilization.

[0064] In Comparative Example 8, the amount of styrene-maleic anhydride copolymer used was too much, the bending deflection of the composite was too small, it was too easy to break, and the flexibility was poor.

Claims

1. A polystyrene composite material, characterized in that: By weight, the components include: Polystyrene 100 parts; 15-35 parts of styrene-butadiene copolymer; 30-70 parts of styrene-maleic anhydride copolymer; The content of styrene structural components in the styrene-butadiene copolymer is 30-41 wt%; The content of maleic anhydride structural component in the styrene-maleic anhydride copolymer is 14-25 wt %.

2. The polystyrene composite material according to claim 1, characterized in that: The polystyrene has a melting index of 6.5-15 g / 10 min at 200° C. and 5 kg.

3. The polystyrene composite material according to claim 1, characterized in that: The mass percentage of the styrene structural component in the styrene-butadiene copolymer is 35-40wt%.

4. The polystyrene composite material according to claim 1, characterized in that: The content of maleic anhydride structural component in the styrene-maleic anhydride copolymer is 15-21 wt %.

5. The polystyrene composite material according to claim 1, characterized in that: By weight, the components include: Polystyrene 100 parts; 20-30 parts of styrene-butadiene copolymer; Styrene-maleic anhydride copolymer 40-60 parts.

6. A method for preparing the polystyrene composite material according to claim 1, comprising: The components are weighed according to the proportion, dry-mixed in a mixer, and then melt-extruded and granulated in a twin-screw extruder to obtain a polystyrene composite material.

7. Use of the polystyrene composite material according to any one of claims 1 to 5 in a disposable sampling rod.

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