Modified pmma for eyeglass pin and method of making same

Abstract

The application discloses modified PMMA for glasses pin feet and a preparation method thereof, and belongs to the technical field of high polymer materials. The material is composed of the following components in percentage by weight: PMMA resin 35-45%; (methyl methacrylate-butyl methacrylate-styrene) core-shell copolymer 35-45%; (methyl methacrylate-butadiene-styrene) core-shell copolymer 0-5%; lubricant 0-10%; antioxidant 0.2-0.4%. The application modifies PMMA by using core-shell copolymer, significantly improves the toughness and processing fluidity of the material, reduces the hardness and water absorption, and meanwhile retains the high transparency and high gloss of PMMA. Compared with the existing CA and CAP materials, the composite material of the application does not contain phthalic acid plasticizer, has lower density and more excellent dimensional stability, and is suitable for injection molding preparation of glasses pin feet.

Description

Technical Field

[0001] This invention relates to the field of polymer materials technology, specifically to modified PMMA for use in eyeglass pins and its preparation method. Background Technology

[0002] Eyeglasses injection molding inserts are copper / steel pins (collectively referred to as inserts) that are pushed into the injection mold by a specific pusher plate (usually using a cylinder as the thrust) while the plastic is still in a molten state during the injection molding process. After the melt solidifies, the inserts become an integral part of the eyeglasses temple, allowing the temple to be bent at an adjustable angle.

[0003] Currently, China is the world's largest producer and exporter of eyeglasses. The special materials used for injection molding pins in eyeglasses are cellulose acetate (CA) and cellulose propionate (CAP).

[0004] During the production of "CA", 20-50% of "phthalic acid" plasticizers need to be added to the formula. When used in high-end products, it cannot pass the corresponding EU and US testing and regulatory requirements. "CA" will release odor and precipitate "phthalic acid" for a long time. It not only has a strong acetic acid smell, but also causes the coating to peel off easily after the product is painted and the inserted copper needles to be corroded.

[0005] Currently, CAP material is entirely imported and not produced domestically, resulting in a single source and supply, and a high unit price. CAP material has a high density, which can cause eyeglasses and other products worn on the face to be excessively heavy and uncomfortable to wear.

[0006] Both CAP and CA materials have poor dimensional stability, making products prone to warping. In environments with high humidity and large temperature differences, products are more likely to deform.

[0007] Traditional PMMA material, due to its excessive hardness, causes inserts to fail to be pushed in during injection molding, or to curl up after being pushed in due to the material's rigidity. Furthermore, PMMA lacks toughness and its excessive strength leads to brittle fracture during bending, and it also cannot achieve free-angle bending of the insert pins.

[0008] Therefore, we propose a modified PMMA for eyeglass insert pins and its preparation method. Summary of the Invention

[0009] A modified PMMA for eyeglass insert pins comprises the following components by weight percentage: 35%~45% PMMA resin; 35%~45% (methyl methacrylate-butyl methacrylate-styrene) core-shell copolymer; 0%~5% (methyl methacrylate-butadiene-styrene) core-shell copolymer; 0~10% lubricant; and 0.2%~0.4% antioxidant.

[0010] Preferably, the lubricant is selected from one or more of polyethylene glycol, trioctyl trimellitate, and cyclohexyl methacrylate.

[0011] Preferably, the antioxidant is a compound of a phosphite antioxidant and a hindered phenolic antioxidant. More preferably, the phosphite antioxidant is ADK / PEP-36, and the hindered phenolic antioxidant is AO-80, both added at an amount of 0.2%.

[0012] Preferably, the PMMA resin is selected from LG IF830 or Chi Mei CM-205.

[0013] Preferably, the (methyl methacrylate-butyl methacrylate-styrene) core-shell copolymer is Zhongyuan Chemical M230, and the (methyl methacrylate-butadiene-styrene) core-shell copolymer is Zhongyuan Chemical M270.

[0014] The present invention also provides a method for preparing the above-mentioned modified PMMA composite material, comprising the following steps: S1 weighs each component according to the formula and puts it into a high-speed mixer, and mixes it evenly at 300 rpm and 40℃. S2. The mixture is dried at 80°C for 2 hours. S3 adds the dried mixture to a twin-screw extruder and melts and granulates it within a temperature range of 195℃~215℃; S4 feeds the extruded granules into an elevated homogenizing chamber and homogenizes them at 80°C for 30 minutes to obtain a modified PMMA composite material.

[0015] The present invention also provides the application of the above-mentioned modified PMMA composite material in the preparation of eyeglass inserts, and eyeglass inserts made from the material. Beneficial effects

[0016] 1. Compared with ordinary PMMA, modified PMMA has significant improvements in indicators such as bending strength, elongation at break, and notched impact strength, which characterizes toughness. It improves the problems of insufficient toughness and excessive strength of PMMA, which prevents free adjustment of pins and brittle fracture.

[0017] 2. Modified PMMA and CA / CAP are very similar in terms of flexural strength and notched impact strength, which characterizes toughness, and can achieve free adjustment of the pins; however, the water absorption rate is significantly reduced, which can significantly reduce the deformation, warping and aging hydrolysis of products caused by high relative humidity.

[0018] 3. Modified PMMA is superior to CA and CAP in terms of dimensional stability. Attached Figure Description

[0019] Figure 1 A comparison chart of the physical properties of modified PMMA and PMMA; Figure 2 A comparison chart of the physical property data of modified PMMA and CA / CP; Figure 3 This is a comparison chart of the dimensional stability of modified PMMA and CA / CP. Detailed Implementation

[0020] The present invention will be further described in detail below with reference to specific embodiments.

[0021] Weigh each component according to the following weight percentages: PMMA (LG IF830) 40%; (Methyl methacrylate-butyl methacrylate-styrene) core-shell copolymer (Kongyeon Chemical M230) 40%; (Methyl methacrylate-butadiene-styrene) core-shell copolymer (Kongyeon Chemical M270) 2%; polyethylene glycol 8.6%; trioctyl trimellitate 5%; cyclohexyl methacrylate 4%; ADK / PEP-36 0.2%; AO-80 0.2%.

[0022] The above components were put into a high-speed mixer and mixed evenly at 300 rpm and 40°C. The mixture was then dried at 80°C for 2 hours. The dried mixture was added to a twin-screw extruder and melt-extruded into granules at a temperature range of 195°C to 215°C. The extruded granules were fed into an elevating homogenizing chamber and homogenized at 80°C for 30 minutes to obtain the modified PMMA composite material.

[0023] The resulting composite material was injection molded to prepare eyeglass pins. The product was transparent and had a high gloss. The insertion process was smooth, the pins did not curl or deform, and the bending test showed good performance with no brittle fracture. Example

[0024] Weigh each component according to the following weight percentages: PMMA (Chimei CM-205) 42%; (methyl methacrylate-butyl methacrylate-styrene) core-shell copolymer (Kongyuan Chemical M230) 42%; polyethylene glycol 7.6%; trioctyl trimellitate 4%; cyclohexyl methacrylate 4%; ADK / PEP-36 0.2%; AO-80 0.2%.

[0025] The modified PMMA composite material was prepared using the same method as in Example 1. The properties of the obtained material were basically the same as those in Example 1, and all met the requirements for the preparation of eyeglass pins. Example

[0026] Weigh the components as follows by weight percentage: PMMA (LG IF830) 38%; (methyl methacrylate-butyl methacrylate-styrene) core-shell copolymer (Kongyeon Chemical M230) 45%; (methyl methacrylate-butadiene-styrene) core-shell copolymer (Kongyeon Chemical M270) 4%; polyethylene glycol 5.6%; trioctyl trimellitate 3%; cyclohexyl methacrylate 4%; ADK / PEP-36 0.2%; AO-80 0.2%.

[0027] The modified PMMA composite material was prepared using the same method as in Example 1. The resulting material also exhibited excellent toughness, transparency, and dimensional stability, making it suitable for the fabrication of eyeglass pins.

[0028] To avoid invalid reissues, it should be noted that although embodiments of the present invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principles and spirit of the present invention, the scope of which is defined by the appended claims and their equivalents.

[0029] In addition, throughout this document, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, without necessarily requiring or implying any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus.

Claims

1. A modified PMMA for use with eyeglass insert pins, characterized in that, The mass percentages of the formulation components are as follows: PMMA 35%~45%, (methyl methacrylate-butyl methacrylate-styrene) core-shell copolymer 35%~45%, (methyl methacrylate-butadiene-styrene) core-shell copolymer 0%~5%, lubricant 0~10%, antioxidant 0.2%~0.4%.

2. The modified PMMA for eyeglass insert pins according to claim 1, characterized in that, The lubricant is selected from one or more of polyethylene glycol, trioctyl trimellitate, and cyclohexyl methacrylate.

3. The modified PMMA for eyeglass insert pins according to claim 1, characterized in that, The antioxidant is a compound of phosphite antioxidants and hindered phenolic antioxidants.

4. The modified PMMA for eyeglass insert pins according to claim 3, characterized in that, The phosphite antioxidant is ADK / PEP-36, and the hindered phenolic antioxidant is AO-80, both added at an amount of 0.2%.

5. A method for preparing modified PMMA for eyeglass insert pins as described in any one of claims 1 to 4, characterized in that, Includes the following steps: S1. Weigh each component according to the ratio, put them into a high-speed mixer, and mix them evenly at 300 rpm and 40℃. S2. Dry the mixture at 80℃ for 2 hours; S3. Add the dried mixture to a twin-screw extruder and melt-extrude and granulate it within a temperature range of 195℃~215℃. S4. The extruded granules are fed into an elevating homogenization chamber and homogenized at 80°C for 30 minutes to obtain the modified PMMA composite material.

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