Thermoplastic elastomer for eraser and preparation method thereof

Abstract

The invention discloses a thermoplastic elastomer for an eraser and a preparation method of the thermoplastic elastomer, and belongs to the technical field of thermoplastic elastomer materials. The thermoplastic elastomer for the eraser is prepared from the following raw materials in parts by weight: 20 to 30 parts of styrene-butadiene block copolymer, 10 to 20 parts of polyolefin resin, 30 to 40 parts of softening operation oil, 30 to 50 parts of filler and 5 to 10 parts of tackifying resin, the filler comprises one or more of calcium carbonate, talcum powder, kaolin, mica, wollastonite, barium sulfate, carbon black, white carbon black, titanium dioxide and anhydrous sodium sulphate; the tackifying resin comprises one or more of monomer resin, poly alpha olefin, coumarone resin and phenolic resin; the thermoplastic elastomer material prepared by the invention has good temperature resistance, yellowing resistance, high transparency and high erasing rate, and can be widely applied to high-grade eraser products with high added value.

Description

Technical Field

[0001] The invention belongs to the technical field of thermoplastic elastomer materials, in particular to a thermoplastic elastomer used for an eraser and a preparation method thereof. Background Art

[0002] Thermoplastic elastomers are a type of high-performance composite material with physical properties between plastic and rubber. They are easy to process and have the elasticity of rubber, and are known as the "third generation of rubber". This material has the functionality of vulcanized rubber at room temperature, and the plasticity and repeated processability of thermoplastics at high temperatures. Compared with traditional thermosetting rubbers, thermoplastic elastomers have the advantages of simple molding, energy-saving processing equipment, high cost performance, and recyclable materials and nozzle materials. While meeting the functions, appearance, and touch, they also have significant advantages in energy saving and environmental protection. With the widespread application of thermoplastic elastomers in the automotive industry, building materials and home furnishings, electronic appliances, medical and health care, and consumer products, rubber products other than pneumatic tires are seeking to use thermoplastic elastomers as substitutes.

[0003] At present, thermoplastic elastomer materials are used in cultural products in a large number of cases. However, in the application of most thermoplastic elastomer materials in erasers, transparency is poor, the word erasure rate is not high during wiping, and its poor mechanical properties are very easy to break or poor weather resistance is very easy to yellow. In order to adapt to the application of thermoplastic elastomer in some high added value, aesthetic aspects, usually it will be limited to the transparency of appearance, or the transparency is good, and the word erasure rate is not good. Therefore, a preparation method of a thermoplastic elastomer with high transparency and high word erasure rate applied to erasers is proposed. Summary of the invention

[0004] In view of the deficiencies in the prior art, the present invention proposes a thermoplastic elastomer for erasing rubber and a preparation method thereof.

[0005] A thermoplastic elastomer for an eraser comprises the following raw materials in parts by weight: 20-30 parts of styrene-butadiene block copolymer, 10-20 parts of polyolefin resin, 30-40 parts of softening operating oil, 30-50 parts of filler and 5-10 parts of tackifying resin;

[0006] The filler includes one or more of calcium carbonate, talc, kaolin, mica, wollastonite, barium sulfate, carbon black, white carbon black, titanium dioxide and sulphur dioxide; the tackifying resin includes one or more of monomer resin, polyalphaolefin, coumarone resin and phenolic resin.

[0007] Preferably, the styrene-butadiene block copolymer includes one or more of styrene-butadiene-styrene block copolymer, styrene-ethylene-butylene-styrene block copolymer and styrene-ethylene-propylene-styrene block copolymer.

[0008] Preferably, the polyolefin resin includes one or more of copolymer polypropylene, homopolypropylene and polyethylene.

[0009] Preferably, the softening process oil includes one or more of paraffin oil, cycloalkane oil, aromatic hydrocarbon oil and straight-chain alkane oil.

[0010] Preferably, 0-1 parts by weight of a lubricant is also included.

[0011] Preferably, 0-2 parts by weight of an antioxidant is also included.

[0012] Preferably, the lubricating dispersant includes one or more of erucamide, oleamide, zinc stearate, magnesium stearate, silicone and polyethylene wax.

[0013] Preferably, the antioxidant is one or more of hindered phenols, phosphites, diaryl secondary amines, p-phenylenediamine, ketoamines and aldehyde amines.

[0014] A preparation method for a thermoplastic elastomer for erasing rubber comprises the following preparation steps:

[0015] Mix 20-30 parts by weight of styrene-butadiene block copolymer and 30-40 parts by weight of softening process oil, stir, and let stand;

[0016] Then, 10-20 parts by weight of a polyolefin resin, 30-50 parts by weight of a filler, 5-10 parts by weight of a tackifying resin, 0-1 parts by weight of a lubricant and 0-2 parts by weight of an antioxidant are added, followed by stirring to obtain a premix semi-finished product;

[0017] The premix semi-finished product is melted, extruded and granulated to obtain the finished product.

[0018] Preferably, the standing time is 12 hours.

[0019] The beneficial effects of the present invention include:

[0020] The thermoplastic elastomer for eraser prepared by the present invention is mainly made of environmentally friendly novel styrene-butadiene block copolymer, and low-viscosity environmentally friendly operating oil with a kinematic viscosity of 32cst at 40°C is added to improve the fluidity and processability of the material; a tackifying resin is added to improve the erasability rate of the material, and a filler activated by zinc stearate is added without changing the transparency; and a thermoplastic elastomer material with high environmental protection grade, high transparency and high erasability rate can be prepared by optimizing the arrangement of each component in the formula. Compared with commercially available materials, the environmental protection, weather resistance, transparent aesthetics and erasability rate are greatly improved, and the design requirements of high-end eraser materials can be met.

[0021] The invention optimizes the production steps through reasonable production process design, and can complete the production of thermoplastic elastomer by only one-step extrusion method. The production process is simple, stable, easy to control, environmentally friendly and has low equipment requirements, which is beneficial to large-scale industrial production. DETAILED DESCRIPTION

[0022] The technical solutions in the embodiments of the present invention are described clearly and completely. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0023] Example 1

[0024] A highly transparent and high erasability thermoplastic elastomer for erasers is characterized in that it is prepared from the following components in parts by weight: 20 parts of styrene-butadiene block copolymer, 10 parts of polyolefin resin, 30 parts of softening process oil, 30 parts of filler, 8.5 parts of tackifying resin, 1 part of lubricating dispersant, and 0.5 part of antioxidant.

[0025] The styrene-butadiene block copolymer is a styrene-ethylene-propylene-styrene block copolymer with a styrene content of 31%, and the plasticizer is a plasticizer having a flash point greater than 200°C and a kinematic viscosity greater than 15 mm at 40°C. 2 / s paraffin oil, the filler is a mixture of 50% 800-mesh sodium sulfate and 50% 800-mesh talc, the tackifying resin is C5, the lubricant is a mixture of 30% erucamide and 70% zinc stearate, and the antioxidant is hindered phenols.

[0026] The preparation method of the thermoplastic elastomer specifically comprises the following steps:

[0027] (1) The styrene-butadiene block copolymer and the softening process oil were put into a high-speed stirrer in sequence, stirred at a speed of 300 r / min for 30 minutes, and allowed to stand for 12 hours.

[0028] (2) putting the polyolefin resin, filler, tackifying resin, lubricant, and antioxidant into a high-speed mixer and stirring at a speed of 100 r / min for 10 minutes to obtain a premix semi-finished product;

[0029] (3) Add the semi-finished premix into an extruder, control the processing temperature of the plasticizing and melting zone and the melt conveying zone, use a vacuum pump to evacuate the tail section of the extruder, and melt, extrude, and granulate the premix in the extruder to obtain a finished product.

[0030] Preferably, the extruders in steps (2) and (3) are both co-rotating twin-screw extruders, with a feed speed of 100 r / min, a screw speed of 500 r / min, and a screw aspect ratio of 40;

[0031] In the steps (2) and (3), the temperature of the first section of the solid conveying zone of the extruder is set to 140°C, and the temperatures of the remaining sections are 150°C / 160°C / 170°C / 180°C / 190°C / 200°C / 190°C / 180°C / 170°C.

[0032] Example 2

[0033] A highly transparent and high erasability thermoplastic elastomer for erasers is characterized in that it is prepared from the following components in parts by weight: 20 parts of styrene-butadiene block copolymer, 10 parts of polyolefin resin, 30 parts of softening process oil, 30 parts of filler, 8.5 parts of tackifying resin, 1 part of lubricating dispersant, and 0.5 part of antioxidant.

[0034] The styrene-butadiene block copolymer is a styrene-ethylene-propylene-styrene block copolymer with a styrene content of 31%, and the plasticizer is a plasticizer having a flash point greater than 200°C and a kinematic viscosity greater than 15 mm at 40°C. 2 / s paraffin oil, the filler is a mixture of 50% 1250 mesh sodium sulphate and 50% 1250 mesh talc, the tackifying resin is C5, the lubricant is a mixture of 30% erucamide and 70% zinc stearate, and the antioxidant is hindered phenols.

[0035] The preparation method of the thermoplastic elastomer specifically comprises the following steps:

[0036] (1) The styrene-butadiene block copolymer and the softening process oil were put into a high-speed stirrer in sequence, stirred at a speed of 300 r / min for 30 minutes, and allowed to stand for 12 hours.

[0037] (2) putting the polyolefin resin, filler, tackifying resin, lubricant, and antioxidant into a high-speed mixer and stirring at a speed of 100 r / min for 10 minutes to obtain a premix semi-finished product;

[0038] (3) Add the semi-finished premix into an extruder, control the processing temperature of the plasticizing and melting zone and the melt conveying zone, use a vacuum pump to evacuate the tail section of the extruder, and melt, extrude, and granulate the premix in the extruder to obtain a finished product.

[0039] Preferably, the extruders in steps (2) and (3) are both co-rotating twin-screw extruders, with a feed speed of 100 r / min, a screw speed of 500 r / min, and a screw aspect ratio of 40;

[0040] In the steps (2) and (3), the temperature of the first section of the solid conveying zone of the extruder is set to 140°C, and the temperatures of the remaining sections are 150°C / 160°C / 170°C / 180°C / 190°C / 200°C / 190°C / 180°C / 170°C.

[0041] Example 3

[0042] A highly transparent and high erasability thermoplastic elastomer for erasers is characterized in that it is prepared from the following components in parts by weight: 20 parts of styrene-butadiene block copolymer, 10 parts of polyolefin resin, 30 parts of softening process oil, 30 parts of filler, 8.5 parts of tackifying resin, 1 part of lubricating dispersant, and 0.5 part of antioxidant.

[0043] The styrene-butadiene block copolymer is a styrene-ethylene-propylene-styrene block copolymer with a styrene content of 31%, and the plasticizer is a plasticizer having a flash point greater than 200°C and a kinematic viscosity greater than 15 mm at 40°C. 2 / s paraffin oil, the filler is a mixture of 50% 2500 mesh sodium sulphate and 50% 2500 mesh talc, the tackifying resin is C5, the lubricant is a mixture of 30% erucamide and 70% zinc stearate, and the antioxidant is hindered phenols.

[0044] The preparation method of the thermoplastic elastomer specifically comprises the following steps:

[0045] (1) putting the styrene-butadiene block copolymer and the softening process oil into a high-speed stirrer in sequence, stirring at a speed of 300 r / min for 30 minutes, and standing for 12 hours;

[0046] (2) putting the polyolefin resin, filler, tackifying resin, lubricant, and antioxidant into a high-speed mixer and stirring at a speed of 100 r / min for 10 minutes to obtain a premix semi-finished product;

[0047] (3) Add the semi-finished premix into an extruder, control the processing temperature of the plasticizing and melting zone and the melt conveying zone, use a vacuum pump to evacuate the tail section of the extruder, and melt, extrude, and granulate the premix in the extruder to obtain a finished product.

[0048] Preferably, the extruders in steps (2) and (3) are both co-rotating twin-screw extruders, with a feed speed of 100 r / min, a screw speed of 500 r / min, and a screw aspect ratio of 40;

[0049] In the steps (2) and (3), the temperature of the first section of the solid conveying zone of the extruder is set to 140°C, and the temperatures of the remaining sections are 150°C / 160°C / 170°C / 180°C / 190°C / 200°C / 190°C / 180°C / 170°C.

[0050] Comparative Example 1:

[0051] A highly transparent and high erasability thermoplastic elastomer for erasers is characterized in that it is prepared from the following components in parts by weight: 20 parts of styrene-butadiene block copolymer, 20 parts of polyolefin resin, 40 parts of softening process oil, 50 parts of filler, 10 parts of tackifying resin, 1 part of lubricating dispersant and 0.5 part of antioxidant.

[0052] The styrene-butadiene block copolymer is a styrene-ethylene-propylene-styrene block copolymer with a styrene content of 31%, and the plasticizer is a plasticizer having a flash point greater than 200°C and a kinematic viscosity greater than 15 mm at 40°C. 2 / s paraffin oil, the filler is a mixture of 50% 2500 mesh sodium sulphate and 50% 2500 mesh talc, the tackifying resin is C7, the lubricant is a mixture of 30% erucamide and 70% zinc stearate, and the antioxidant is hindered phenols.

[0053] The preparation method of the thermoplastic elastomer specifically comprises the following steps:

[0054] (1) The styrene-butadiene block copolymer and the softening process oil were put into a high-speed stirrer in sequence, stirred at a speed of 300 r / min for 30 minutes, and allowed to stand for 12 hours.

[0055] (2) putting the polyolefin resin, filler, tackifying resin, lubricant, and antioxidant into a high-speed mixer and stirring at a speed of 100 r / min for 10 minutes to obtain a premix semi-finished product;

[0056] (3) Add the semi-finished premix into an extruder, control the processing temperature of the plasticizing and melting zone and the melt conveying zone, use a vacuum pump to evacuate the tail section of the extruder, and melt, extrude, and granulate the premix in the extruder to obtain a finished product.

[0057] Preferably, the extruders in steps (2) and (3) are both co-rotating twin-screw extruders, with a feed speed of 100 r / min, a screw speed of 500 r / min, and a screw aspect ratio of 40;

[0058] In the steps (2) and (3), the temperature of the first section of the solid conveying zone of the extruder is set to 140°C, and the temperatures of the remaining sections are 150°C / 160°C / 170°C / 180°C / 190°C / 200°C / 190°C / 180°C / 170°C.

[0059] Comparative Example 2:

[0060] A highly transparent and high erasability thermoplastic elastomer for erasers is characterized in that it is prepared from the following components in parts by weight: 30 parts of styrene-butadiene block copolymer, 10 parts of polyolefin resin, 40 parts of softening process oil, 30 parts of filler, 5 parts of tackifying resin, 1 part of lubricating dispersant and 0.5 part of antioxidant.

[0061] The styrene-butadiene block copolymer is a styrene-ethylene-propylene-styrene block copolymer with a styrene content of 31%, and the plasticizer is a plasticizer having a flash point greater than 200°C and a kinematic viscosity greater than 15 mm at 40°C. 2 / s paraffin oil, the filler is a mixture of 50% 2500 mesh sodium sulphate and 50% 2500 mesh talc, the tackifying resin is C9, the lubricant is a mixture of 30% erucamide and 70% zinc stearate, and the antioxidant is hindered phenols.

[0062] The preparation method of the thermoplastic elastomer specifically comprises the following steps:

[0063] (1) The styrene-butadiene block copolymer and the softening process oil were put into a high-speed stirrer in sequence, stirred at a speed of 300 r / min for 30 minutes, and allowed to stand for 12 hours.

[0064] (2) putting the polyolefin resin, filler, tackifying resin, lubricant, and antioxidant into a high-speed mixer and stirring at a speed of 100 r / min for 10 minutes to obtain a premix semi-finished product;

[0065] (3) Add the semi-finished premix into an extruder, control the processing temperature of the plasticizing and melting zone and the melt conveying zone, use a vacuum pump to evacuate the tail section of the extruder, and melt, extrude, and granulate the premix in the extruder to obtain a finished product.

[0066] Preferably, the extruders in steps (2) and (3) are both co-rotating twin-screw extruders, with a feed speed of 100 r / min, a screw speed of 500 r / min, and a screw aspect ratio of 40;

[0067] In the steps (2) and (3), the temperature of the first section of the solid conveying zone of the extruder is set to 140°C, and the temperatures of the remaining sections are 150°C / 160°C / 170°C / 180°C / 190°C / 200°C / 190°C / 180°C / 170°C.

[0068] Test results

[0069] Test method:

[0070] Hardness, measured according to ISO 7619-1, Type A;

[0071] Light transmittance, tested according to AS1462.14:1986;

[0072] Tensile strength, test standard is ISO 37-1, tensile test rate is 500mm / min;

[0073] Word elimination rate, the test standard is QNDL 342-20225.3.4 test;

[0074] Melt flow rate, test standard is ISO 1133-1, method A, 190℃, 2.16kg.

[0075] Table 1 Measurement results

[0076]

[0077]

[0078] It can be seen from the test data in the above table that the thermoplastic elastomer prepared in the present invention has higher light transmittance and erasure rate. Compared with the comparative example, Example 3 has higher light transmittance and erasure rate.

[0079] In Example 1, the mesh number of the thermoplastic elastomer filling is relatively high, the tackifying resin is C5, the overall light transmittance is average, and the word elimination rate is average; compared with Example 1, in Example 2, there is a finer filling, and the tackifying resin is still C5, the light transmittance of the product is improved compared with Example 1, and the word elimination rate is improved; compared with Example 2, a finer filler is replaced in Example 3, so the light transmittance and word elimination rate are relatively excellent; compared with Example 3, the type of tackifying resin is replaced in Comparative Example 1, and C7 with a higher viscosity is used instead, and the light transmittance and word elimination rate are slightly reduced; compared with Comparative Example 1, a higher viscosity tackifying resin C9 is used in Comparative Example 2, and the product performance is that the word elimination rate and light transmittance are not much changed compared with Comparative Example 1; overall, the process parameters have not changed, and can meet the normal production granulation requirements; the coarseness of the filler and the viscosity of the tackifying resin affect the light transmittance, word elimination rate and fluidity of the material.

[0080] In the description of this specification, the description with reference to the terms "one embodiment", "example", "specific example", etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0081] The above shows and describes the basic principles, main features and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments, and the above embodiments and descriptions are only for explaining the principles of the present invention. Without departing from the spirit and scope of the present invention, the present invention may have various changes and improvements, and these changes and improvements all fall within the scope of the present invention to be protected.

Claims

1. A thermoplastic elastomer for an eraser, characterized in that, The method comprises the following raw materials in parts by weight: 20-30 parts of styrene-butadiene block copolymer, 10-20 parts of polyolefin resin, 30-40 parts of softening process oil, 30-50 parts of filler and 5-10 parts of tackifying resin; The filler includes one or more of calcium carbonate, talc, kaolin, mica, wollastonite, barium sulfate, carbon black, white carbon black, titanium dioxide and sulphur dioxide; the tackifying resin includes one or more of monomer resin, polyalphaolefin, coumarone resin and phenolic resin.

2. The thermoplastic elastomer for erasing rubber according to claim 1, characterized in that, The styrene-butadiene block copolymer includes one or more of styrene-butadiene-styrene block copolymer, styrene-ethylene-butylene-styrene block copolymer and styrene-ethylene-propylene-styrene block copolymer.

3. The thermoplastic elastomer for erasing rubber according to claim 1, characterized in that, The polyolefin resin includes one or more of copolymer polypropylene, homopolypropylene and polyethylene.

4. The thermoplastic elastomer for erasing rubber according to claim 1, characterized in that, The softening operation oil includes one or more of paraffin oil, cycloalkane oil, aromatic hydrocarbon oil and straight-chain alkane oil.

5. The thermoplastic elastomer for eraser according to claim 1, characterized in that, Also included is 0-1 parts by weight of a lubricant.

6. The thermoplastic elastomer for eraser according to claim 1, characterized in that, Also included is 0-2 parts by weight of an antioxidant.

7. The thermoplastic elastomer for eraser according to claim 5, characterized in that, The lubricating dispersant includes one or more of erucamide, oleamide, zinc stearate, magnesium stearate, silicone and polyethylene wax.

8. The thermoplastic elastomer for eraser according to claim 6, characterized in that, The antioxidant is one or more of hindered phenols, phosphites, diaryl secondary amines, p-phenylenediamine, ketone amines and aldehyde amines.

9. A method for preparing a thermoplastic elastomer for use with an eraser, characterized in that: The method comprises the following preparation steps: Mix 20-30 parts by weight of styrene-butadiene block copolymer and 30-40 parts by weight of softening process oil, stir, and let stand; Then, 10-20 parts by weight of a polyolefin resin, 30-50 parts by weight of a filler, 5-10 parts by weight of a tackifying resin, 0-1 parts by weight of a lubricant and 0-2 parts by weight of an antioxidant are added, followed by stirring to obtain a premix semi-finished product; The premix semi-finished product is melted, extruded and granulated to obtain the finished product.

10. The preparation method according to claim 9, characterized in that: The standing time is 12 hours.

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