High-transparency and low-haze PC fiber-added product and preparation method thereof

Abstract

The invention discloses a high-transparency and low-haze PC fiber-added product and a preparation method thereof. Firstly, a semitransparent PCGF product is obtained by optimizing glass fibers, the infiltration effect of the glass fibers and PC resin is improved through polyacrylic resin (infiltration improver), the transmittance of the product is finally further improved, the haze is reduced, and the obtained product has the advantages of being high in transmittance, low in haze, high in modulus and the like and is widely applied to the field of electronic and electric appliances such as OA equipment.

Description

Technical Field

[0001] The invention belongs to the technical field of polymer materials, and in particular relates to a high-transparency, low-haze PC fiber-reinforced product and a preparation method thereof. Background Art

[0002] Polycarbonate is one of the five general engineering plastics with many advantages. It is widely used in many industries, especially in the fields of electronics. As one of the major branches of PC modified products, PCGF products have excellent rigidity and dimensional stability, which broadens the application scenarios of PC products. However, because the refractive index of glass fiber and PC is different, the alloys prepared by ordinary fiber-added products are not transparent, which loses its advantages in some high-end application scenarios.

[0003] In the prior art, patent CN107541036A uses compounded ground glass fibers to obtain transparent products. However, in reality, changing the aspect ratio of the glass fibers does not change the refractive index. On the contrary, the increase in interfaces due to grinding will further reduce the transmittance. Therefore, this patent does not effectively solve the problem.

[0004] Patents CN100515710C, CN101514080B, etc. change the refractive index of glass fiber itself by adding substances such as TiO2, so as to be close to PC resin to obtain translucent materials, but the patented products can only obtain translucent products, and the haze remains at a relatively high level.

[0005] Patent CN118620368A uses special oxides such as niobium pentoxide and zirconium dioxide to change the refractive index of the glass fiber to 1.576, thereby obtaining a product with a transmittance of up to 90%. However, the above oxides are expensive and there are currently no circulating products on the market, so they cannot be actually mass-produced.

[0006] Patent CN104419190A uses a wetting flame retardant to obtain high flame retardant properties. In essence, it adds flame retardants such as the P series to improve the wettability of glass fiber and matrix resin to obtain high transparency. However, the biggest disadvantage of this flame retardant system is that it reduces the heat resistance of the product. It cannot be used in many fields, especially when high ball pressure temperature is required. In addition, BDP cannot change the refractive index of the glass fiber itself, and the difference in refractive index between interfaces is also unavoidable.

[0007] Therefore, the existing technical means all have their own limitations and cannot maintain the advantages of PC itself, thus losing application in many fields. Summary of the invention

[0008] The present invention overcomes the defects of the above-mentioned solutions, provides a high-transparency, low-haze PC fiber-added (PCGF) product and provides a preparation method thereof.

[0009] To achieve the above object, the present invention is implemented by the following technical solutions:

[0010] First, the present invention provides a high-transparency, low-haze PC fiber-added product, which comprises the following components:

[0011] Polycarbonate 68-94.8%,

[0012] Glass fiber 5-30%,

[0013] Wetting improver 0.1-1.0%,

[0014] Other additives 0.1-1.0%.

[0015] The polycarbonate of the present invention is an aromatic polycarbonate, preferably a bisphenol A polycarbonate. Preferably, when the test conditions are 300°C and 1.2kg, the melt flow index of PC is between 3-60g / 10min, preferably between 10-35g / 10min, and more preferably between 15-35g / 10min. Available commercial products of polycarbonate include CLARNATE series products of Wanhua Chemical, MAKROLON series products of Covestro, LEXAN series products of Sabic, PANLITE series products of Teijin, TARFLON series products of Idemitsu, PRIMALLOY series products of Mitsubishi Chemical, INFINO series products of Samsung, LUPOY series products of LG Chemical, WONDERLITE series products of Chimei Industrial, etc.

[0016] The glass fiber of the present invention is an alkali-free short fiber, preferably with a diameter of 9-16 μm and a length of 2-6 mm;

[0017] In a preferred embodiment of the present invention, the glass fiber of the present invention is preferably a glass fiber having a refractive index close to that of polycarbonate, preferably a glass fiber having a refractive index of 1.55-1.6.

[0018] The wettability improving agent of the present invention is a polyacrylic acid resin solution, wherein the polyacrylic acid resin preferably has a molecular weight of 500 to 5000 and a pH value of 2 to 4.

[0019] Preferably, the solvent of the polyacrylic acid resin solution is selected from one or more polar solvents such as water or methanol, glycol, etc., and the concentration of the solution is preferably 0.01-0.5 wt%.

[0020] The polyacrylic acid resin of the present invention is preferably a carbomer series, and specific examples of suitable brands include one or more of POLYACRYLIC ACID 5,000, CARBOMER 1622, CARBOMER 672, CARBOMER 690, and Carbopol 941.

[0021] The other additives described in the present invention are selected from one or more combinations of lubricants, antioxidants, compatibilizers, ultraviolet light absorbers, infrared absorbers, heat stabilizers, metal passivators, colorants, coupling agents, foaming agents, hydrolysis resistance agents, chain extenders, flow modifiers, matting agents, antistatic agents, reinforcing agents, fillers, light diffusers, metallic pigments, and pearlescent powders.

[0022] The lubricant described in the present invention includes E wax, AHS, etc., and applicable manufacturers include Faji, Zhejiang Jiayao, Clariant, etc.

[0023] The antioxidant is a combination of one or more of hindered phenols, phosphites, thioesters, benzofurans, acryl-modified phenols and hydroxylamine antioxidants.

[0024] The other additives described in the present invention can be added according to actual needs.

[0025] The reason why PCGF products are opaque is the difference in refractive index between interfaces, which includes both the interface between PC resin and glass fiber (interface 1) and the interface of the voids between PC and glass fiber due to poor infiltration (the voids often retain small molecules such as volatile gases of the material and are not in a completely vacuum state, i.e., interface 2). On the one hand, the refractive index of PC and glass fiber itself will not change due to the addition of third-party substances. The present invention preferably selects glass fiber raw materials with optimized refractive index to make it as close as possible to the refractive index of PC resin (reducing the influence of interface 1); on the other hand, the present invention obtains the maximum infiltration of glass fiber and PC resin matrix through infiltration improvement additives such as polyacrylic resin, reduces or even eliminates the existence of the above-mentioned interface 2, and thus obtains a highly transparent and low-haze PCGF product.

[0026] The highly transparent, low-haze PC fiber-reinforced product of the present invention can achieve a light transmittance of 88% (2mm), a haze of 2.5 (2mm), and has both high strength and high modulus.

[0027] The present invention further provides a method for preparing the above-mentioned highly transparent, low-haze PC fiber-added product, comprising the following steps: 1. fully premixing polycarbonate and other optional additives according to a proportion (defined as a base material);

[0028] 2. Prepare the polyacrylic acid resin into a solution and heat it for standby use (defined as a wetting improver);

[0029] 3. Add the above base material through the main feeding port, feed the impregnation improving agent and glass fiber through the side feeding port, perform melt extrusion, granulate and dry to obtain.

[0030] In step 2 of the present invention, the polyacrylic acid resin solution is heated to 60-80° C. for standby use, and a solution side feeding method is adopted to avoid the shortcomings of the polyacrylic acid resin itself, that is, acidity and low heat resistance, and better achieve the effect of improving the wetting.

[0031] In the process of melt extrusion in step 3 of the present invention, the temperature is controlled at 240-280°C.

[0032] The high-transparency, low-haze PC fiber-added product of the present invention is widely used in the field of OA equipment such as notebook computers and printers.

[0033] Compared with the prior art, the present invention has the following beneficial effects:

[0034] The present invention improves the wetting effect of glass fiber and PC resin by polyacrylic acid resin (wetting improver), and reduces the gap between the two. Since commercially available glass fiber is generally sized with epoxy resin (commercially available glass fiber, the manufacturer will use a wetting agent for sizing, such as CN113880458A, CN114230198A, etc.), after the addition of polyacrylic acid resin, the acidic groups such as carboxyl react with the epoxy groups in the epoxy resin to achieve full wetting with the surface of the glass fiber, and then the excess carboxyl group further reacts with the terminal hydroxyl group of the PC resin, thereby achieving bridging of the glass fiber and the PC resin, improving the wetting performance between the two, and finally further improving the transmittance of the product and reducing the haze. In addition, the present invention preferably uses the raw material of the glass fiber, and uses the glass fiber with a refractive index close to that of the PC resin, so as to further improve the interface, improve the transmittance of the product and reduce the haze. DETAILED DESCRIPTION

[0035] In order to facilitate the understanding of the present invention, the present invention will be further described below in conjunction with examples. It should be understood that the following examples are only for a better understanding of the present invention and do not mean that the present invention is limited to the following examples.

[0036] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art to which the invention belongs. The term "and / or" as may be used herein includes any and all combinations of one or more of the associated listed items.

[0037] Main raw material sources

[0038] 2220: Bisphenol A polycarbonate produced by interfacial phosgene method, melt flow index is 20g / 10min (300℃, 1.2kg), produced by Wanhua Chemical Group Co., Ltd.

[0039] 2350: Bisphenol A polycarbonate produced by interfacial phosgene method, melt flow index is 35g / 10min (300℃, 1.2kg), produced by Wanhua Chemical Group Co., Ltd.

[0040] CARBOMER 690: polyacrylic acid resin, Nanjing Songguan Biotechnology Co., Ltd.;

[0041] Carbopol 941: polyacrylic acid resin, Hangzhou Jingda Flower Industry Co., Ltd.;

[0042] PETS: Pentaerythritol stearate, lubricant, produced by Lonza, USA;

[0043] B900: antioxidant, produced by BASF;

[0044] ECS307-3-K / HR: Glass fiber, purchased from Chongqing International, refractive index 1.57-1.58;

[0045] T442A: Glass fiber, Taishan fiberglass, refractive index is about 1.52;

[0046] UV360: ultraviolet light absorber, commercially available.

[0047] Main test methods

[0048] Melt index test is carried out according to ASTM D1238 standard test, condition 300℃ / 1.2kg;

[0049] The tensile properties were tested using ASTM D638, condition 5mm / min;

[0050] The light transmittance and haze were tested using ASTM D1003-21, with a thickness of 2 mm.

[0051] Examples and Comparative Examples

[0052] The preparation methods of the PC fiber-added products of the embodiments and comparative examples of the present invention are as follows:

[0053] 1. Premix polycarbonate and other optional additives according to proportion (defined as base material);

[0054] 2. Prepare a 0.1 wt% aqueous solution of polyacrylic acid resin and heat it to 80° C. for standby use (defined as a wetting improver);

[0055] 3. Add the above base material through the main feeding port, add the impregnation improving agent and glass fiber from the side feeding port, the melting section temperature is 270°C, the temperature of the sixth, seventh and eighth zones is set to 240°C, melt extrusion is carried out, granulation and drying are carried out, and the product is obtained.

[0056] Table 1 Example raw materials and performance test

[0057]

[0058]

[0059] Table 2 Comparative Examples Raw Materials and Performance Tests

[0060]

[0061] From Examples 1-8 and Comparative Examples 1-4, the present invention provides polyacrylic acid resin as a wetting improver, preferably glass fiber with a refractive index close to that of polycarbonate, so that the obtained PC fiber-added product has high transparency and low haze. From Example 3 and Comparative Example 2, when the wetting improver is added in excess, the transparency of the product is almost not affected, but the melt index of the product becomes larger, resulting in a decrease in strength.

[0062] It is easy to understand that the above embodiments are only examples for clear explanation and do not mean that the present invention is limited thereto. For ordinary technicians in the relevant field, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the implementation methods here. The obvious changes or modifications derived from this are still within the protection scope of the present invention.

Claims

1. A high-transparency, low-haze PC fiber-added product, characterized in that: This product contains the following ingredients: Polycarbonate 68-94.8%, Glass fiber 5-30%, Wetting improver 0.1-1.0%, Other additives 0.1-1.0%; Wherein, the refractive index of the glass fiber is 1.55-1.

6.

2. The high-transparency, low-haze PC fiber-added product according to claim 1, characterized in that: The polycarbonate is an aromatic polycarbonate, preferably bisphenol A polycarbonate; preferably, under the test conditions of 300° C. and 1.2 kg, the melt flow index of the polycarbonate is 3-60 g / 10 min, preferably 10-35 g / 10 min.

3. The high-transparency, low-haze PC fiber-added product according to claim 1, characterized in that: The glass fiber is an alkali-free short fiber with a diameter of 9-16 μm and a length of 2-6 mm.

4. The high-transparency, low-haze PC fiber-added product according to claim 1, characterized in that: The wettability improving agent is a polyacrylic acid resin solution, wherein the molecular weight of the polyacrylic acid resin is 500-5000 and the pH value is 2-4.

5. The high-transparency, low-haze PC fiber-added product according to claim 4, characterized in that: The polyacrylic acid resin is a carbomer series, and is preferably selected from one or more of POLYACRYLIC ACID 5000, CARBOMER 1622, CARBOMER 672, CARBOMER 690, and Carbopol 941.

6. The high-transparency, low-haze PC fiber-added product according to claim 4, characterized in that: The solvent of polyacrylic acid resin solution is water, methanol, di One or more of alkane and ethylene glycol; the concentration of the polyacrylic acid resin solution is preferably 0.01-0.5wt%.

7. The high-transparency, low-haze PC fiber-reinforced product according to any one of claims 1 to 6, characterized in that: The other auxiliary agents include one or more of antioxidants, lubricants, ultraviolet light absorbers, colorants, antistatic agents, and matting agents.

8. The method for preparing a high-transparency, low-haze PC fiber-reinforced product according to any one of claims 1 to 7, characterized in that: The following steps are involved: A. mixing polycarbonate and other optional additives according to proportion to obtain a base material; B. preparing a polyacrylic acid resin into a solution and heating the solution for standby use; C. Add the above base material through the main feeding port, feed the impregnation improving agent and glass fiber through the side feeding port, perform melt extrusion, granulate and dry to obtain.

9. The preparation method according to claim 7, characterized in that: The heating temperature in step B is 60-80°C; preferably, the temperature during the melt extrusion process in step C is controlled at 240-280°C.

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