Foaming light-weight TPE eraser material and preparation method thereof

Abstract

The invention discloses a foamed light-weight TPE eraser material and a preparation method thereof, and relates to the technical field of stationery, and the foamed light-weight TPE eraser material is prepared from the following raw materials in parts by weight: 100 parts of styrene block copolymer, 100-200 parts of white oil, 20-80 parts of resin, 10-40 parts of compatilizer, 150-700 parts of filler, 0.1-1 part of antioxidant, 0.1-1 part of light stabilizer, 1-5 parts of slipping agent and 8-20 parts of foaming agent. By accurately controlling the foaming temperature and process, a uniform and stable foam structure is formed in the material, so that the overall weight of the product is reduced, the portability is improved, the negative influence of foaming on the strength and elasticity of the material is avoided, the light weight and durability are both considered, and the requirements of consumers on light weight and good use of stationery are met.

Description

Technical Field

[0001] This invention relates to the field of stationery technology, and more specifically, to a foamed lightweight TPE eraser material and its preparation method. Background Technology

[0002] Erasers, as an important part of everyday stationery, are mainly used to remove marks left by pencils (graphite or colored pencils) on paper or other surfaces. Their working principle is to remove graphite particles or pigments from the paper surface through the physical action generated by friction, thereby achieving the removal effect.

[0003] Currently, there are many types of eraser materials on the market, the most common being rubber, PVC (polyvinyl chloride), thermoplastic vulcanized rubber (TPR), and thermoplastic elastomer (TPE). Before the advent of polymer erasers, people usually used breadcrumbs as erasing tools. In 1770, the British engineer Edward Naime accidentally discovered that rubber was more effective than breadcrumbs when used as an eraser, and rubber erasers began to be gradually promoted. However, early rubber erasers had obvious defects: unprocessed rubber was easily perishable, and the eraser body was dense and smooth, making it difficult to shed lint during erasing; it only absorbed graphite on its surface, and repeated rubbing would only make the paper dirtier. In 1839, Charles Goodyear discovered that adding oil, fillers, and other raw materials to rubber, along with sulfur for vulcanization, could significantly improve the quality of the rubber. The resulting eraser was soft and linted easily, and this technology allowed rubber erasers to be used for a long time. However, rubber transforms into a thermosetting material after vulcanization, making the product unrecyclable and causing environmental pollution. Against this backdrop, thermoplastic erasers emerged. Erasers made from PVC powder, plasticizers, and fillers do not require vulcanization, resulting in higher production efficiency and a soft texture. Furthermore, PVC, as a thermoplastic, is recyclable, making it the material of choice for most erasers on the market. However, PVC releases harmful gases during processing, damaging production equipment and posing health risks. Additionally, the plasticizers and additives in PVC can adversely affect health with prolonged use, potentially causing mild poisoning. This is especially true for minors with weaker immune systems; excessive plasticizer concentrations can easily lead to headaches, nausea, and inflammation of the eyes, nose, and throat. To protect consumer health, my country has added phthalate ester compound testing to the "National Toy Safety Technical Specification" (GB6675), with limits largely adopted from the EU's Reach Plasticizer Directive. Similarly, the revised "General Safety Requirements for School Supplies" (GB21027, draft for comments) includes phthalate ester plasticizer quality requirements for erasers, specifying clear limits (DBP+BBP+DEHP≤1g / kg, DNOP+DINP+DIDP≤1g / kg). In the EU, Directive 1999 / 815 / EEC, published in 1999, clearly states that the content of six plasticizers in polyvinyl chloride (PVC) children's toys and related products intended for children under 3 years old must not exceed 0.1%.

[0004] TPR erasers are made from thermoplastic rubber and are currently widely used in the market. TPR erasers are environmentally friendly, non-toxic, and safe, free of phthalic plasticizers (6P, 16P), nonylphenol (NP), and polycyclic aromatic hydrocarbons (PAHs), and comply with environmental standards such as RoHS, REACH (SVHC), and EN71. They have good elasticity, a soft feel, and can be processed using extrusion and injection molding processes. They possess good colorability and tactile properties, excellent processing performance, require no vulcanization, and are recyclable to reduce costs. They are suitable for producing various export-grade erasers for dolls, toys, and cartoon characters, making them particularly suitable for children. However, TPR erasers also have several drawbacks, such as high specific gravity, high hardness, a sticky feel, poor shavings formation, poor erasing smoothness, low erasure rate, susceptibility to breakage, and easy aging.

[0005] With the continuous improvement of people's living standards, environmental protection, children's health, and the pursuit of a good user experience have become key concerns. Under this trend, environmentally friendly TPE eraser materials are gradually entering the market. However, erasers on the market are generally heavy, with a specific gravity greater than water. Moreover, in both domestic and international patents and markets, there are no extruded foamed eraser materials or products that produce less debris and have good linearity.

[0006] In view of the problems existing in the above-mentioned prior art, the development of a foamed lightweight eraser material that takes into account both smooth wiping and the characteristics of scattering shavings is of great practical significance and market value. Summary of the Invention

[0007] To address the problems in related technologies, this invention proposes a foamed lightweight TPE eraser material and its preparation method. This addresses the difficulty in combining foamability with suitable processing methods in existing eraser materials, thus hindering the production of lightweight eraser products. Furthermore, after foaming, key performance characteristics such as wiping smoothness, shavings formation, and erasure rate are difficult to guarantee.

[0008] The technical solution of this invention is implemented as follows:

[0009] One aspect of the present invention:

[0010] A foamed lightweight TPE eraser material and its preparation method are disclosed, comprising the following raw materials in parts by weight: 100 parts of styrene block copolymer, 100-200 parts of white oil, 20-80 parts of resin, 10-40 parts of compatibilizer, 150-700 parts of filler, 0.1-1 parts of antioxidant, 0.1-1 parts of light stabilizer, 1-5 parts of slip agent, and 8-20 parts of foaming agent, wherein;

[0011] The specific details of each raw material are as follows:

[0012] Styrene block copolymers: including one or more mixtures of styrene-ethylene-butene-styrene block copolymers (SEBS), styrene-ethylene-propylene-styrene block copolymers (SEPS), and styrene-ethylene-ethylene-propylene-styrene block copolymers (SEEPS). Depending on the eraser processing method (e.g., extrusion, injection molding), styrene block copolymers of different molecular weights or mixtures of different molecular weights can be selected for use. Among them, hydrogenated high molecular weight SEBS exhibits excellent toughness, heat resistance, and aging resistance, making it a preferred material for everyday consumer goods, stationery, toys, and other industries. Extensive experimental verification has shown that using a special structure of SEPS (SEPS polymerized from isoprene using 3,4 polymerization) can significantly improve the material's tactile feel and erasure rate.

[0013] White oil: also known as white mineral oil, which can be made from paraffin oil or naphthenic oil, with a viscosity of less than 200 mg / L at 40 degrees Celsius. 2 / s, its main function is to reduce the hardness of materials and improve the processing performance of products. Priority should be given to paraffin oils with low viscosity, high flash point, good compatibility, and excellent resistance to yellowing. These types of paraffin oils can further improve the aging performance and feel of products, while reducing the risk of oil seepage.

[0014] Filler: This is an inorganic mineral powder or artificially manufactured inorganic powder, specifically one or more of the following: calcium carbonate, talc, barium sulfate, glass powder, kaolin, diatomaceous earth, and wollastonite, with high-quality calcium carbonate powder being preferred. The particle size of the filler is greater than 400 mesh, preferably 600-1250 mesh. Multiple fillers with different mesh sizes can also be mixed to optimize material properties.

[0015] Resins include one or more of the following: α-methylstyrene monomer, metallocene polyolefin resin, atactic polypropylene (APP), olefin elastomers, ethylene-vinyl acetate copolymer, waxes, paraffin wax, polyethylene wax, polypropylene wax, and C5 petroleum resin. Selecting a suitable resin can bind the eraser shavings together into strips, improving the erasure rate of the material and thus ensuring the cleanliness of the paper surface.

[0016] Compatibilizers include one or more mixtures of maleic anhydride-grafted styrene-ethylene-butene-styrene block copolymers (SEBS-g-MAH), maleic anhydride-grafted polyolefin elastomers (POE-g-MAH), maleic anhydride-grafted polyethylene (PE-g-MAH), and maleic anhydride-grafted polypropylene (PP-g-MAH). Compatibilizers have an amphoteric structure; some groups in their molecules are compatible with fillers and acrylic elastomers, while others are compatible with TPE polymers. This allows for the strong bonding of two materials with significantly different properties, effectively improving the dispersion of fillers in TPE, enhancing the overall performance of TPE eraser materials, and reducing whitening on the eraser surface.

[0017] Antioxidants: Selected from one or more of antioxidants such as antioxidant 168, antioxidant 1010, and antioxidant 1076. Their main function is to inhibit the oxidative degradation of materials during processing and use, and to extend the service life of products.

[0018] Light stabilizers are one or more of ultraviolet absorbers and light stabilizers that can slow down the aging rate of materials under light conditions, maintain product performance stability, and prevent discoloration.

[0019] Slip agents include one or more of the following: silicone masterbatch, polydimethylsiloxane, erucamide, oleamide, ethylene bis-stearamide (EBS), and stearic acid. Slip agents improve processing performance during material molding, enhance the feel of the eraser surface, and, more importantly, significantly reduce the coefficient of friction between the eraser surface and paper, making erasing smoother.

[0020] Foaming agent: including physical microsphere foaming agent, with a foaming temperature range of 120-200℃. It is preferred to use high-quality foaming agent with a lower foaming temperature to better achieve the foaming effect of the material and prepare lightweight eraser products.

[0021] Another aspect of the present invention:

[0022] A method for preparing a foamed lightweight TPE eraser material includes the following steps:

[0023] Step S1: Mix the styrene block copolymer with white oil in advance according to the weight parts, and then fully absorb the oil.

[0024] Step S2: Add filler, resin, compatibilizer, antioxidant, light stabilizer and slip agent to the product obtained in step S1 according to the weight parts, and blend them.

[0025] Step S3: The blend product obtained in step S2 is melt-blended at 150℃~200℃ using a twin-screw extruder, granulated and cooled to obtain a semi-finished material;

[0026] Step S4: Add foaming agent to the semi-finished material obtained in step S3 according to the weight parts and mix. Then, perform intensive mixing and granulation, open milling and granulation or twin-screw melt blending and granulation at 60℃~100℃ to obtain TPE eraser finished granules.

[0027] Step S5: The TPE eraser granules obtained in step S4 are extruded in a single screw at 120℃~160℃ to obtain a foamed low-resistance TPE eraser.

[0028] Among them, the specific gravity of the foamed low-resistivity TPE eraser obtained in step S5 is less than 1.

[0029] The beneficial effects of this invention are:

[0030] This invention's foamed low-resistance TPE eraser material achieves breakthroughs and integration in multiple dimensions of performance. In terms of core performance, the scientific formulation of styrene block copolymers with specific resins and slip agents solves the problems of high erasing resistance and rough feel associated with traditional erasers. Furthermore, the resin's adhesive effect on the shavings improves upon the previous product's difficulty in cleaning up scattered shavings, making the erasing process smoother and the shavings easier to form into strips. Simultaneously, relying on the characteristics of specially structured styrene block copolymers (such as SEPS polymerized from isoprene 3,4), it ensures efficient removal of graphite particles during erasing, guaranteeing effective erasure. Regarding lightweight properties, the introduction of a physical microsphere foaming agent breaks the industry convention that erasers must be "greater than water." By precisely controlling the foaming temperature and process, a uniform and stable cell structure is formed within the material, reducing the overall weight of the product, improving portability, and avoiding the negative impact of foaming on material strength and elasticity. This balances lightweight design with durability, meeting consumers' demands for lightweight and easy-to-use stationery.

[0031] Furthermore, the materials and processes of this invention exhibit significant sustainability advantages and production flexibility. In terms of environmental friendliness, the selected raw materials all comply with stringent international environmental standards such as RoHS, REACH (SVHC), and EN71, and are free of harmful substances such as phthalic plasticizers, nonylphenol, and polycyclic aromatic hydrocarbons. Moreover, the production process requires no vulcanization treatment, avoiding pollution from vulcanizing agents in traditional rubber eraser processing, and also mitigating the health risks of harmful gas release and plasticizer migration during PVC eraser processing. From raw materials to production, the entire chain protects human health and the ecological environment, making it particularly suitable for the safety needs of children's stationery. In terms of industrial applications, the material formulation can be adjusted to be compatible with various mainstream processing methods such as extrusion and injection molding. Whether producing regular block erasers or customized cartoon-shaped erasers, stable mass production can be achieved. At the same time, thermoplastic TPE materials are recyclable, and products can be recycled through reasonable processes after they are scrapped, reducing resource waste. The adoption of mature processes such as twin-screw melt blending and single-screw extrusion also lowers the threshold for enterprises to transform their production lines, making it easier to quickly implement and put into production. This provides the stationery industry with a new material solution that combines environmental protection, functionality and economy, and promotes the industry's upgrade towards green and high-quality development. Attached Figure Description

[0032] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0033] Figure 1 This is a flowchart illustrating an embodiment of the present invention.

[0034] Figure 2 This is a flowchart illustrating Embodiment 2 of the present invention;

[0035] Figure 3 This is a flowchart illustrating Embodiment 3 of the present invention. Detailed Implementation

[0036] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention are within the scope of protection of the present invention.

[0037] Example 1

[0038] According to embodiments of the present invention, a foamed lightweight TPE eraser material is provided, comprising the following raw material formulation by weight:

[0039] The styrene block copolymer is SEBS: 100 parts;

[0040] The white oil is paraffin oil, with a viscosity of 10 mm at 40℃. 2 / s: 120 copies;

[0041] The resin is random polypropylene APP: 50 parts;

[0042] The compatibilizer is SEBS-g-MAH: 25 parts;

[0043] The filler is calcium carbonate powder, 800 mesh: 400 parts;

[0044] The antioxidant ratio is 10:10:0.5 parts;

[0045] The light stabilizer is UV-531, an ultraviolet absorber, at 0.5 parts.

[0046] The slip agent is erucamide: 3 parts;

[0047] The foaming agent is a physical microsphere foaming agent with a foaming temperature of 140℃: 14 parts.

[0048] like Figure 1 As shown, the preparation method of the foamed lightweight TPE eraser material according to an embodiment of the present invention includes the following steps:

[0049] S1. Mix 100 parts SEBS with 150 parts paraffin oil and stir at room temperature for 30 minutes to allow for full oil absorption.

[0050] S2, add 50 parts APP, 25 parts SEBS-g-MAH, 400 parts 800 mesh calcium carbonate powder, 0.5 parts 1010 antioxidant, 0.5 parts UV-531 light stabilizer, and 3 parts erucamide to the above oil-absorbed mixture, put it into a high-speed mixer, mix at 80°C for 15 minutes to obtain a blend.

[0051] S3. The blend is added to a twin-screw extruder. The temperatures of each zone of the extruder are set to 150℃, 170℃, 180℃, 190℃, and 200℃, and the screw speed is 300r / min. After melt blending, the mixture is granulated and cooled to obtain semi-finished granules.

[0052] S4. Add 14 parts of physical microsphere foaming agent to the semi-finished granules, mix them in an internal mixer at 100°C for 10 minutes, and then granulate them to obtain the finished TPE eraser granules.

[0053] S5. The finished product granules are added to a single-screw extruder. The extrusion temperature is set to 120℃, 140℃, 150℃, and 160℃, and the screw speed is 200r / min. After extrusion molding, a foamed lightweight TPE eraser is obtained.

[0054] Example 2

[0055] According to embodiments of the present invention, a foamed lightweight TPE eraser material is provided. It comprises the following raw material formulation by weight:

[0056] The styrene block copolymer is 100 parts SEPS (containing 10 parts of isoprene 3,4-polymerized).

[0057] The white oil is a naphthenic oil with a viscosity of 50 mmHg at 40°C. 2 / s: 150 copies;

[0058] The resin is an ethylene-vinyl acetate copolymer: 20 parts;

[0059] The compatibilizer is POE-g-MAH: 10 parts;

[0060] The filler is talc powder, 600 mesh: 300 parts;

[0061] The antioxidant ratio is 168:0.1 parts;

[0062] The light stabilizer is 770 parts light stabilizer (0.1 parts).

[0063] The slip agent is silicone masterbatch: 1 part;

[0064] The foaming agent is a physical microsphere foaming agent with a foaming temperature of 120℃: 10 parts.

[0065] like Figure 2 As shown, the foamed lightweight TPE eraser material and its preparation method according to an embodiment of the present invention include the following steps:

[0066] S1, mix 100 parts SEPS with 100 parts naphthenic oil, stir at room temperature for 25 minutes to fully absorb the oil;

[0067] S2, add 20 parts of ethylene-vinyl acetate copolymer, 10 parts of POE-g-MAH, 300 parts of 600-mesh talc, 0.1 parts of 168 antioxidant, 0.1 parts of 770 light stabilizer, and 1 part of silicone masterbatch to the oil-absorbed mixture, put it into a high-speed mixer, and mix at 70°C for 12 minutes to obtain a blend;

[0068] S3. The blend is added to a twin-screw extruder. The temperatures of each zone of the extruder are set to 150℃, 160℃, 170℃, 180℃, and 190℃, and the screw speed is 250r / min. The blend is melt-blended, granulated, and cooled to obtain semi-finished granules.

[0069] S4. Add 8 parts of physical microsphere foaming agent to the semi-finished granules, and mill at 80°C for 8 minutes in a two-roll mill, and then granulate to obtain TPE eraser finished granules.

[0070] S5. The finished product granules are added to a single-screw extruder. The extrusion temperature is set to 120℃, 130℃, 140℃, and 140℃, and the screw speed is 180r / min. After extrusion molding, a foamed lightweight TPE eraser is obtained.

[0071] Example 3

[0072] According to embodiments of the present invention, a foamed lightweight TPE eraser material is provided. It comprises the following raw material formulation by weight:

[0073] The styrene block copolymer is a mixture of SEBS and SEEPS in a mass ratio of 1:1: 100 parts;

[0074] The white oil is paraffin oil, with a viscosity of 180 mmHg at 40℃. 2 / s: 200 copies;

[0075] The resin is a mixture of C5 petroleum resin and polyethylene wax at a mass ratio of 1:2: 80 parts;

[0076] The compatibilizer is PP-g-MAH: 40 parts;

[0077] The filler is a mixture of calcium carbonate powder and barium sulfate at a mass ratio of 3:1, with a particle size of 1250 mesh and a ratio of 600 parts.

[0078] The antioxidant ratio is 1076:1.

[0079] The light stabilizer is a mixture of UV absorber UV-327 and light stabilizer 944 in a mass ratio of 1:1: 1 part;

[0080] The slip agent is a mixture of polydimethylsiloxane and EBS in a mass ratio of 1:1: 5 parts;

[0081] The foaming agent is a physical microsphere foaming agent with a foaming temperature of 150℃: 20 parts.

[0082] like Figure 3 As shown, the preparation method of the foamed lightweight TPE eraser material according to an embodiment of the present invention includes the following steps:

[0083] S1, mix 100 parts of the mixture of SEBS and SEEPS with 200 parts of paraffin oil, stir at room temperature for 35 minutes to allow for full oil absorption;

[0084] S2, add 80 parts of a mixture of C5 petroleum resin and polyethylene wax, 40 parts of PP-g-MAH, 600 parts of a mixture of 1250 mesh calcium carbonate powder and barium sulfate, 1 part of 1076 antioxidant, 1 part of a mixture of UV-327 and 944, and 5 parts of a mixture of polydimethylsiloxane and EBS to the oil-absorbed mixture, put it into a high-speed mixer, and mix at 90°C for 18 minutes to obtain a blend;

[0085] S3. The blend is added to a twin-screw extruder. The temperatures of each zone of the extruder are set to 160℃, 180℃, 190℃, 200℃, and 200℃, and the screw speed is 350r / min. The blend is melt-blended, granulated, and cooled to obtain semi-finished granules.

[0086] S4, add 20 parts of physical microsphere foaming agent to the semi-finished granules, use twin-screw melt blending granulation, set the temperature to 100℃ and the screw speed to 300r / min, to obtain TPE eraser finished granules;

[0087] S5. The finished product granules are added to a single-screw extruder. The extrusion temperature is set to 130℃, 160℃, 165℃, and 165℃, and the screw speed is 220r / min. After extrusion molding, a foamed lightweight TPE eraser is obtained.

[0088] Using the above technical solutions, the foamed low-resistivity TPE erasers prepared in Examples 1, 2, and 3 were selected as test samples. At the same time, commercially available mainstream PVC erasers (reference sample 1) and commercially available TPR erasers (reference sample 2) were selected as comparative samples to verify the performance advantages of the products of the present invention.

[0089] The eraser rate was determined according to the "Eraser" standard (QB / T2309-2020). A standard test pattern was drawn on writing paper with a basis weight of 70 g / m² using a standard pencil (HB). The paper was erased five times with an eraser, and the reflectance of the paper before and after erasing was measured using a spectrophotometer. The eraser rate was calculated as follows: (Eraser rate = (Reflectance after erasing - Reflectance before erasing) / (Reflectance of blank paper - Reflectance before erasing) × 100%). Specific gravity was determined according to the "Determination of Density of Non-Foamed Plastics Part 1: Immersion Method, Liquid Specific Gravity Bottle Method and Titration Method" (GB / T1033.1-2008). The sample density (specific gravity) was determined using the immersion method at a test temperature of 23℃. Wiping smoothness was measured using a tensile testing machine to simulate manual wiping. The wiping speed was set to 50 mm / s, and the wiping pressure to 5 N. The average friction force during the wiping process was recorded; the lower the friction force, the better the wiping smoothness. For the strip formation test, a 10cm × 10cm black area was drawn on test paper using a standard pencil. The area was then erased in the same direction with an eraser. The results were observed and recorded to determine whether the resulting strips could naturally coalesce into strips. The strips were rated as "Excellent (≥90% strip formation), Good (70%-89% strip formation), Medium (50%-69% strip formation), Poor (<50% strip formation)". For environmental compliance, in accordance with RoHS 2.0 (2011 / 65 / EU), REACH (SVHC list, as of May 2024), and EN71-3 (2019) standards, the content of heavy metals (lead, cadmium, mercury, hexavalent chromium, etc.) was detected using inductively coupled plasma optical emission spectrometry (ICP-OES), and the content of phthalates, nonylphenol, polycyclic aromatic hydrocarbons, and other harmful substances was detected using gas chromatography-mass spectrometry (GC-MS) to determine whether the standards were met. For aging resistance testing, samples were placed in an aging test chamber with a set temperature of 70℃, relative humidity of 85%, and ultraviolet radiation intensity of 0.71 W / m² (340 nm) for 168 hours. After aging, the hardness change rate of the samples was measured (hardness testing was conducted according to "Test Methods for Indentation Hardness of Vulcanized Rubber or Thermoplastic Rubber Part 1: Shore Hardness Tester Method (Shore A and Shore D)" (GB / T531.1-2008)). A smaller hardness change rate indicates better aging resistance. Specific experimental data are shown in Table 1.

[0090] Table 1 Comparison of Experimental Data

[0091]

[0092]

[0093] As shown in Table 1, the erasure rates of Examples 1, 2, and 3 are all above 83%, reaching a maximum of 88.1%, significantly higher than Control Sample 1 (75.2%) and Control Sample 2 (78.8%), indicating that the product of the present invention has a superior erasing effect and can more thoroughly remove pencil marks. Meanwhile, the specific gravity of Examples 1, 2, and 3 is all less than 1, allowing them to float on water, achieving a lightweight design; while the specific gravity of Control Sample 1 (PVC) and Control Sample 2 (TPR) is greater than 1, at 1.45 g / cm³. 3 and 1.22g / cm 3 It is relatively heavy and not very portable.

[0094] In addition, the average friction force of Examples 1, 2 and 3 is 1.18-1.31N, which is much lower than that of Control Sample 1 (1.85N) and Control Sample 2 (1.56N), indicating that the product of the present invention has less resistance, a smoother feel and a better user experience during wiping.

[0095] Furthermore, the paper scrap forming properties of Examples 1, 2, and 3 all reached the "Excellent" level, with ≥90% of the scrap naturally coalescing into strips, facilitating cleaning and maintaining the cleanliness of the paper surface. Control Sample 1 (PVC) only reached the "Medium" level, and Control Sample 2 (TPR) reached the "Good" level, with the scrap being dispersed and more difficult to clean. Simultaneously, Examples 1, 2, and 3 all complied with environmental standards such as RoHS 2.0, REACH (SVHC), and EN71-3, with no excessive levels of harmful substances. Control Sample 1 (PVC) had excessive levels of hexavalent chromium and phthalates, posing potential risks to human health and the environment. Although Control Sample 2 (TPR) met environmental standards, its overall performance was inferior to the product of this invention. Moreover, the hardness change rate of Examples 1, 2, and 3 after a 168-hour aging test was only 4.8-5.5%, far lower than that of Control Sample 1 (12.3%) and Control Sample 2 (8.7%), indicating that the product of this invention has superior aging resistance, a longer service life, and maintains good performance and feel even after long-term use.

[0096] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Those skilled in the art, upon considering the disclosure in the specification and embodiments, will readily conceive of other embodiments of this disclosure. This application is intended to cover any variations, uses, or adaptations of this disclosure that follow the general principles of this disclosure and include common knowledge or customary techniques in the art not disclosed herein. The specification and embodiments are to be considered exemplary only, and the true scope and spirit of this disclosure are indicated by the claims.

[0097] It should be understood that this disclosure is not limited to the precise structures described above and shown in the accompanying drawings, and various modifications and changes can be made without departing from its scope. The scope of this disclosure is limited only by the appended claims.

Claims

1. A foamed lightweight TPE eraser material, characterized in that, Prepared from the following raw materials by weight parts, including: styrene block copolymer 100 parts, white oil 100-200 parts, resin 20-80 parts, compatibilizer 10-40 parts, filler 150-700 parts, antioxidant 0.1-1 parts, light stabilizer 0.1-1 parts, slip agent 1-5 parts and foaming agent 8-20 parts, wherein; The styrene block copolymer includes a mixture of one or more of SEBS, SEPS, SEEPS; the white oil has a viscosity of less than 200 mm 2 / s at 40 degrees Celsius; the filler is inorganic mineral powder or artificial inorganic powder; and the foaming agent is a physical microsphere foaming agent with a foaming temperature of 120-200 degrees Celsius.

2. The foamed lightweight TPE eraser material according to claim 1, characterized in that, The styrene block copolymer contains isoprene using 3,4 polymerization SEPS.

3. The foamed lightweight TPE eraser material according to claim 1, characterized in that, The white oil is paraffin oil or naphthenic oil.

4. The foamed lightweight TPE eraser material according to claim 1, characterized in that, The filler is one or more of calcium carbonate, talc, barium sulfate, glass powder, kaolin, diatomite, wollastonite, and the particle size of the filler is greater than 400 mesh.

5. The foamed lightweight TPE eraser material according to claim 4, characterized in that, The particle size of the filler is 600-1250 mesh.

6. The foamed lightweight TPE eraser material according to claim 1, characterized in that, The resin includes a mixture of one or more of alpha-methylstyrene monomer, metallocene polyolefin resin, random polypropylene, olefin elastomer, ethylene-vinyl acetate copolymer, wax, paraffin wax, polyethylene wax, polypropylene wax, and carbon five petroleum resin.

7. The foamed lightweight TPE eraser material according to claim 1, characterized in that, The compatibilizer includes a mixture of one or more of SEBS-g-MAH, POE-g-MAH, PE-g-MAH, and PP-g-MAH.

8. The foamed lightweight TPE eraser material according to claim 1, characterized in that, The antioxidant is one or more of antioxidant 168, antioxidant 1010, and antioxidant 1076; the light stabilizer is one or more of ultraviolet absorber and light stabilizer; the slip agent includes a mixture of one or more of silicone masterbatch, polydimethylsiloxane, erucic acid amide, oleic acid amide, EBS, and stearic acid.

9. A method of making a foamed lightweight TPE eraser material, characterized by, Including the following steps: Step S1, the styrene block copolymer is mixed with white oil in advance according to weight parts, and the oil is fully absorbed; Step S2, the filler, resin, compatibilizer, antioxidant, light stabilizer, and slip agent are added to the product obtained in step S1 according to weight parts, and blending is performed; Step S3, the blended product obtained in step S2 is passed through a double screw melt blending at 150-200°C, granulated and cooled to obtain a semi-finished material; Step S4, the foaming agent is added to the semi-finished material obtained in step S3 according to weight parts, mixed, and subjected to internal mixing granulation, open mill granulation, or double screw melt blending granulation at 60-100°C to obtain TPE eraser finished particles; Step S5, the TPE eraser finished particles obtained in step S4 are extruded in a single screw at 120-160°C to obtain foamed low resistance TPE eraser finished products.

10. The method of making a foamed lightweight TPE eraser material according to claim 9, characterized in that, The foamed low resistance TPE eraser finished products prepared in step S5 have a specific gravity less than 1.

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