Environment-friendly color paste for silica gel as well as preparation method and application of color paste

Abstract

The invention relates to the technical field of environment-friendly color paste, and provides environment-friendly color paste for silica gel as well as a preparation method and application thereof. The color paste comprises the following components in percentage by mass: 15-35% of an organic pigment, 15-30% of an inorganic pigment, 35-45% of a silicone-based dispersion medium and 5-10% of an auxiliary agent. The organic pigment is selected from at least one of a benzimidazolone yellow pigment and an isoindoline yellow pigment; the inorganic pigment is selected from at least one of a titanium yellow pigment, a bismuth yellow pigment and a nickel yellow pigment. Through an organic-inorganic composite strategy, the advantage of bright color of the organic pigment is exerted, and the characteristics of high heat resistance and high covering power of the inorganic pigment are utilized, so that the optimization of comprehensive performance is realized. The paint has the characteristics of no toxicity, environment friendliness, high heat resistance, excellent dispersion stability and storage stability and the like.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of environment-friendly color paste, and particularly relates to an environment-friendly color paste for silica gel, a preparation method and application thereof. BACKGROUND

[0002] Silica gel is widely used in construction, electronics, automobiles and home decoration as an important sealing and bonding material. In the practical application of silica gel, coloring treatment is often needed to meet the requirements of aesthetics and identification.

[0003] Traditional silica gel coloring mainly relies on lead chromate (PbCrO4) as a yellow colorant. Due to its bright color, strong hiding power and low cost, lead chromate has long dominated the field of silica gel coloring. However, lead chromate contains a large amount of heavy metal elements such as lead and chromium, which can cause serious harm to the environment and human health during production and use. These heavy metal ions can migrate from silica gel products into the human body through skin contact or respiratory inhalation, leading to chronic poisoning and even carcinogenic risk.

[0004] With the increasing awareness of environmental protection and the increasing strictness of regulations, the use of pigments containing heavy metals such as lead, chromium and cadmium has been banned internationally. The EU RoHS Directive (2011 / 65 / EU) and the REACH Regulation (EC 1907 / 2006) strictly limit the use of heavy metals in commodities, which makes the traditional lead chromate color paste face the situation of being eliminated.

[0005] Existing alternatives to lead chromate mainly include single organic pigment color paste, single inorganic pigment color paste and simple organic-inorganic mixed color paste. Although single organic pigment color paste has bright color, it generally has poor heat resistance and insufficient weather resistance, and is prone to discoloration during high-temperature processing of silica gel and has weak ultraviolet resistance when used outdoors. Single inorganic pigment color paste has good heat resistance and weather resistance, but has relatively weak tinting strength and insufficient bright color, making it difficult to meet the requirements of some application scenarios.

[0006] More importantly, the dispersion stability and storage stability of existing alternatives in the silica gel system are generally not ideal. The silica gel system has unique chemical properties, and the compatibility of the color paste is relatively high. Existing alternative color pastes often have problems such as uneven dispersion, sedimentation and caking, which affect the quality and appearance of silica gel products. In addition, these alternative color pastes have poor stability during storage and are prone to pigment sedimentation and stratification, shortening the storage period of the products.

[0007] Existing alternatives also have the problem of poor compatibility with the silica gel matrix, which may affect the curing performance of the silica gel and the physical and mechanical properties of the final product, limiting its use in high-demand application fields. SUMMARY

[0008] The present application aims at providing an environment-friendly color paste for silica gel, a preparation method and application thereof, and solving the technical problem of environmental pollution and health hazards caused by heavy metals such as lead and chromium in the existing chrome yellow silica gel color paste.

[0009] In order to achieve the above-mentioned purposes, the present application provides an environment-friendly color paste for silica gel, comprising the following components in percentage by mass: organic pigment: 15% to 35%; inorganic pigment: 15% to 30%; silicone-based dispersion medium: 35% to 45%; auxiliary agent: 5% to 10%; The organic pigment is selected from at least one of benzimidazolone yellow pigment and isoindoline yellow pigment; and the inorganic pigment is selected from at least one of titanium yellow pigment, bismuth yellow pigment and nickel yellow pigment.

[0010] Optionally, the organic pigment is selected from at least one of benzimidazolone yellow PY154, benzimidazolone yellow PY151, benzimidazolone yellow PY175, isoindoline yellow PY139 and isoindoline yellow PY185.

[0011] Optionally, the inorganic pigment is selected from at least one of titanium-nickel yellow PY53, titanium-chromium yellow PY162 and bismuth vanadate yellow PY184.

[0012] Optionally, the silicone-based dispersion medium is selected from at least one of polydimethylsiloxane and vinyl silicone oil.

[0013] Optionally, the auxiliary agent comprises a dispersant, a thixotropic agent and a stabilizer. The dispersant comprises modified polydimethylsiloxane, the thixotropic agent comprises fumed silica, and the stabilizer comprises a silane coupling agent.

[0014] Optionally, the fineness of the color paste is not greater than 15 μm, and the heat-resistant temperature of the color paste is not lower than 300℃.

[0015] The present application further provides a preparation method of the above-mentioned environment-friendly color paste for silica gel, comprising: drying the organic pigment and the inorganic pigment; mixing the silicone-based dispersion medium with the auxiliary agent; adding the pretreated pigment into the mixed dispersion system for dispersion grinding; defoaming the ground color paste.

[0016] Optionally, the drying condition is 80℃ to 100℃, and the drying time is 4 to 6 hours.

[0017] Optionally, the dispersion grinding comprises high-speed dispersion and mechanical grinding, and the grinding fineness is less than 10 microns. The rotation speed of the high-speed dispersion is 1000-1500 r / min, and the time is 20-30 minutes; the mechanical grinding is performed 3-5 times by a three-roll grinder or a basket sand mill.

[0018] Optionally, the defoaming treatment is performed under vacuum condition, the vacuum degree is -0.08 to -0.1 MPa, and the time is 20-30 minutes.

[0019] The application further provides application of the color paste for environment-friendly silica gel in silica gel coloring.

[0020] Compared with the prior art, the color paste for environment-friendly silica gel is designed by compounding organic pigments and inorganic pigments, and realizes an environment-friendly and non-toxic silica gel coloring scheme. The color paste has high heat resistance (≥300 DEG C) and high weather resistance while maintaining excellent coloring effect, has good compatibility with a silicone-based dispersion medium, can realize uniform dispersion and long-term stability of the color paste in a silica gel system, and meets the demand of modern industry for environment-friendly silica gel coloring materials.

[0021] The preparation method provided by the application comprises the process steps of drying pretreatment, dispersion system preparation, high-efficiency grinding and vacuum defoaming, and improves the dispersion uniformity and storage stability of the color paste. In particular, the auxiliary system composed of modified polydimethylsiloxane, fumed silica and silane coupling agent can improve the dispersion performance of the organic pigments and the inorganic pigments in the silicone-based medium, ensures that the fineness of the prepared color paste is less than 10 microns, and there is no sedimentation and stratification phenomenon within 6 months, and can provide persistent and stable coloring effect for silica gel products. DETAILED DESCRIPTION

[0022] The application will be described in more detail below, in which preferred embodiments of the application are described, it should be understood that those skilled in the art can modify the application described herein while still achieving the advantageous effects of the application. Therefore, the following description should be understood as extensive knowledge for those skilled in the art, and not as a limitation on the application.

[0023] The application will be described in more detail below, in which preferred embodiments of the application are described, it should be understood that those skilled in the art can modify the application described herein while still achieving the advantageous effects of the application. Therefore, the following description should be understood as extensive knowledge for those skilled in the art, and not as a limitation on the application.

[0024] Based on the inspiration of the present application, those skilled in the art can form new technical solutions by cross combination of different embodiments without causing technical contradictions, and such modifications should be considered to fall within the protection scope of the present application.

[0025] Example 1 The environment-friendly color paste for silica gel provided by the embodiment of the present application is composed of organic pigments, inorganic pigments, silicone-based dispersion medium and additives, and each component is calculated by mass percentage, including the following components: 15-35% of organic pigments; 15-30% of inorganic pigments; 35-45% of silicone-based dispersion medium; and 5-10% of additives.

[0026] The organic pigments are selected from at least one of benzimidazolone yellow pigments and isoindoline yellow pigments.

[0027] The benzimidazolone yellow pigments and isoindoline yellow pigments have the characteristics of bright color and strong tinting strength, can provide excellent yellow tone, and do not contain heavy metal components, meeting the environmental protection requirements.

[0028] In a specific example, the organic pigments can be selected from at least one of benzimidazolone yellow PY154, benzimidazolone yellow PY151, benzimidazolone yellow PY175, isoindoline yellow PY139 and isoindoline yellow PY185.

[0029] The inorganic pigments are selected from at least one of titanium yellow pigments, bismuth yellow pigments and nickel yellow pigments.

[0030] The inorganic pigments are mainly added to improve the heat resistance, hiding power and weather resistance of the color paste. The titanium, bismuth and nickel yellow pigments do not contain harmful heavy metals such as lead, cadmium and hexavalent chromium, and can maintain color stability at high temperatures above 300℃.

[0031] In a specific example, the inorganic pigments can be selected from at least one of titanium-nickel yellow PY53, titanium-chromium yellow PY162 and bismuth vanadate yellow PY184.

[0032] The titanium-nickel yellow PY53 has excellent heat resistance and chemical stability; the titanium-chromium yellow PY162 contains chromium elements, but is a trivalent chromium compound, belonging to environment-friendly pigments; and the bismuth vanadate yellow PY184 has good hiding power and weather resistance.

[0033] The embodiment of the present application uses organic-inorganic composite, which not only has the advantages of bright color and strong tinting strength of organic pigments, but also has the characteristics of high heat resistance, strong hiding power and good weather resistance of inorganic pigments, thereby obtaining a composite color paste with excellent comprehensive performance. This composite strategy effectively solves the technical problems of poor heat resistance of single organic pigments and insufficient tinting strength of single inorganic pigments.

[0034] Further, the silicone-based dispersion medium plays a role in dispersing pigment particles and providing fluidity, and at the same time ensures good compatibility of the color paste with the silica gel base material.

[0035] The silicone-based dispersion medium is selected from at least one of polydimethylsiloxane and vinyl silicone oil.

[0036] Among them, polydimethylsiloxane has excellent thermal stability and chemical inertness, and excellent compatibility with silica gel system, preferably α, ω-dihydroxy polydimethylsiloxane; the vinyl silicone oil contains active vinyl groups, which can participate in crosslinking reaction in some silica gel curing system, further improving the compatibility.

[0037] In a specific example, polydimethylsiloxane or vinyl silicone oil can be used alone, or both can be mixed in a certain proportion, preferably mixed in a mass ratio of 1:1 to obtain better comprehensive performance.

[0038] Specifically, the auxiliary agent includes dispersant, thixotropic agent and stabilizer, and the synergistic effect of the three types of auxiliary agents is the key to ensure that the color paste has excellent dispersion stability and storage stability.

[0039] The dispersant includes modified polydimethylsiloxane.

[0040] Modified polydimethylsiloxane refers to a modified product in which a specific functional group is introduced into the polydimethylsiloxane molecular chain, which can effectively reduce the interfacial tension between pigment particles and dispersion medium and improve the dispersion effect of pigments. This modification treatment makes the dispersant not only maintain good compatibility with the silicone-based dispersion medium, but also has excellent dispersion performance.

[0041] The thixotropic agent includes fumed silica.

[0042] Fumed silica is a nanoscale silica powder with a large specific surface area and good thixotropy. Its addition can adjust the rheological properties of the color paste, prevent the settling of pigment particles when at rest, and improve the storage stability.

[0043] The stabilizer includes silane coupling agent.

[0044] Silane coupling agent can form chemical bonds on the surface of organic pigments, improve the bonding force between pigments and silicone-based dispersion medium, and thus improve the dispersion stability. At the same time, silane coupling agent can also improve the surface properties of pigment particles and reduce the occurrence of agglomeration.

[0045] In a specific example, the fineness of the color paste is not more than 15 μm, preferably not more than 10 μm, and more preferably reaches 8 μm or less. The control of fineness directly affects the coloring effect and appearance quality of the color paste, and the smaller the fineness, the more uniform the coloring and the better the gloss.

[0046] The heat-resistant temperature of the color paste is not less than 300 DEG C. The heat resistance ensures that the color paste can meet the needs of silicone in high-temperature processing and use environment, which is an important performance requirement for replacing the medium chrome yellow color paste.

[0047] Further, the environment-friendly color paste for silicone provided by the embodiment of the present application has wide application in silicone coloring.

[0048] The silicone is selected from at least one of liquid silicone rubber, silicone building glue, silicone leather, electronic packaging glue and automobile sealing glue. The addition amount of the color paste is 1% to 5% of the total mass of the silicone. The selection of the addition amount needs to be determined according to the required coloring depth. In general, 1% of the addition amount can obtain a lighter yellow color, and 5% of the addition amount can obtain a darker yellow color. Too little addition amount will not have obvious coloring effect, and too much addition amount can affect the physical properties of the silicone.

[0049] The weather resistance of the silicone product after adding the color paste reaches grade 7 to 8. The weather resistance is an important indicator for measuring the outdoor service life of the silicone product. The weather resistance of grade 7 to 8 means that the silicone product can be used in outdoor environment for a long time without obvious color change.

[0050] In a specific example, the method of adding the color paste into the silicone can adopt mechanical stirring, three-roll grinding or other mixing equipment to ensure uniform dispersion of the color paste in the silicone. The specific selection of the mixing process belongs to the usual means of those skilled in the art.

[0051] In a specific example, the colored silicone can also be prepared into various silicone products through processes such as extrusion molding, injection molding and calendering molding. The specific molding process is determined according to the shape and use of the product.

[0052] In summary, the environment-friendly color paste for silicone provided by the embodiment of the present application realizes the synergistic optimization of performance through the compounding of organic pigments and inorganic pigments. The organic pigments are selected from benzimidazolone and isoindoline yellow pigments, which provide bright color and excellent coloring power. The inorganic pigments are selected from titanium, bismuth and nickel environment-friendly yellow pigments, which ensure high heat resistance and strong hiding power. The silicone-based dispersion medium is polydimethylsiloxane or vinyl silicone oil, which ensures good compatibility with the silicone substrate. The modified polydimethylsiloxane dispersant, fumed silica thixotropic agent and silane coupling agent stabilizer synergistically ensure excellent dispersion stability and storage stability. The environment pollution problem caused by heavy metals in traditional medium chrome yellow color paste can be solved, and the key performance indicators such as coloring power, heat resistance and weather resistance can reach or exceed the level of traditional products, which provides an environment-friendly coloring solution for the silicone industry.

[0053] Embodiment two The embodiment also provides a preparation method of the environment-friendly color paste for silica gel. S1, pigment pretreatment: dry treatment is performed on the organic pigment and the inorganic pigment.

[0054] The pigment often contains a certain amount of water, and the presence of water will affect the dispersion effect and storage stability of the color paste, so it is necessary to remove the water in advance.

[0055] The dry treatment condition is 80-100 DEG C, and the dry time is 4-6 hours. Under this temperature and time condition, the water in the pigment can be effectively removed, and the structure and performance of the pigment will not be adversely affected. If the dry temperature is too low or the dry time is too short, the water will not be completely removed; if the temperature is too high, some organic pigments may be decomposed.

[0056] In a specific example, oven drying, vacuum drying or microwave drying can be used, and the specific drying method is a common means for those skilled in the art, which will not be described here.

[0057] S2, preparation of dispersion system: the silicone-based dispersion medium is mixed with the auxiliary agent.

[0058] During the mixing process, the silicone-based dispersion medium can be heated to 40-50 DEG C, which is beneficial to the dissolution and dispersion of the auxiliary agent and improves the mixing efficiency. The selection of the heating temperature should ensure that the auxiliary agent can be fully dispersed, and the temperature should not be too high to cause the volatilization or decomposition of some components.

[0059] The mixing method can be mechanical stirring, and the stirring speed is usually 800-1000 r / min, and the stirring time is 15-30 minutes until the components are uniformly mixed.

[0060] S3, mixing and grinding: the pretreated pigment is added to the mixed dispersion system for dispersion and grinding.

[0061] The dispersion and grinding include two stages of high-speed dispersion and mechanical grinding, and the grinding fineness is less than 10 microns.

[0062] High-speed dispersion stage: the rotation speed of the high-speed dispersion is 1000-1500 r / min, and the time is 20-30 minutes. The purpose of high-speed dispersion is to initially disperse the pigment agglomerates, so that the pigment particles are initially dispersed in the dispersion medium. The rotation speed and time should be moderate, because too low rotation speed will not have good dispersion effect, and too high rotation speed will introduce too many air bubbles; too short time will not have sufficient dispersion, and too long time will cause temperature rise and affect the performance of the color paste.

[0063] Mechanical grinding stage: the mechanical grinding is carried out 3-5 times by using a three-roll grinder or a basket sand mill. The three-roll grinder can effectively break the pigment agglomerates by strong shearing force generated by the relative movement of three rollers; the basket sand mill realizes fine dispersion of the pigment by impact and grinding action of the grinding medium. The number of grinding times is determined according to the dispersion difficulty of the pigment and the required fineness.

[0064] In a specific example, other types of grinding equipment such as a ball mill, a sand mill, a colloid mill, etc. can also be used, and the specific selection of the equipment and adjustment of the operation parameters are the usual means of the person skilled in the art.

[0065] S4, stabilizing treatment: defoaming treatment is performed on the ground color paste.

[0066] During the grinding process, a certain amount of air bubbles will inevitably be introduced, and if these air bubbles are not removed in time, they will affect the appearance and use performance of the color paste.

[0067] The defoaming treatment is performed under vacuum condition, the vacuum degree is -0.08 to -0.1 MPa, and the time is 20-30 minutes. The appropriate vacuum degree can effectively remove the air bubbles, and at the same time, will not cause adverse effects on other performances of the color paste. If the vacuum degree is too low, the defoaming effect is poor, and if the vacuum degree is too high, some volatile components may be lost.

[0068] In a specific example, the defoaming treatment can also be combined with heating, and the temperature is controlled at 40-60°C, which can further improve the defoaming efficiency.

[0069] Through the above preparation process, the environmentally friendly color paste for silica gel with uniform dispersion and good stability can be obtained. The whole preparation process is simple, the equipment requirement is not high, and it is suitable for industrial production.

[0070] Example three The yellow silica gel color paste obtained in the following experimental examples 1-9 is subjected to performance test according to the embodiment of the present application.

[0071] Experimental example 1 The following components are included by mass percentage: benzimidazolone yellow PY154 (20%), titanium nickel yellow PY53 (15%), polydimethylsiloxane (40%), modified polydimethylsiloxane (3%), fumed silica (1.5%), and silane coupling agent (0.5%).

[0072] Preparation steps: S1: dry benzimidazolone yellow PY154 and titanium nickel yellow PY53 at 85°C for 5 hours respectively; S2: heat the polydimethylsiloxane to 45°C, add the auxiliary agent, and stir at a speed of 800 r / min for 20 minutes; S3: The pretreated pigments were gradually added to the dispersion system, and high-speed dispersion was carried out at a speed of 1200 r / min for 25 minutes, and then three-roll grinding was carried out 4 times, and the fineness reached 8 μm; S4: Defoaming was carried out under a vacuum degree of -0.09 MPa for 25 minutes.

[0073] Experimental Example 2 The following components were included by mass percentage: isoindoline yellow PY139 (18%), titanium chromium yellow PY162 (12%), bismuth vanadate yellow PY184 (8%), vinyl silicone oil (42%), modified polydimethylsiloxane (4%), fumed silica (2.5%), silane coupling agent (1.5%).

[0074] The preparation steps were the same as in Experimental Example 1, and the parameters were adjusted as follows: the heating temperature in S2 was 48°C, the stirring speed was 1000 r / min, and the time was 15 minutes; the high-speed dispersion speed in S3 was 1300 r / min, the time was 20 minutes, and the grinding was carried out 5 times; the vacuum degree in S4 was -0.1 MPa, and the defoaming time was 20 minutes.

[0075] Experimental Example 3 The following components were included: benzimidazolone yellow PY175 (15%), isoindoline yellow PY185 (10%), bismuth vanadate yellow PY184 (10%), a mixture of polydimethylsiloxane and vinyl silicone oil (1:1, 35%), modified polydimethylsiloxane (3.5%), fumed silica (2%), and silane coupling agent (1.5%).

[0076] The preparation steps were the same as in Experimental Example 1, and the parameters were adjusted as follows: the heating temperature in S2 was 42°C, the stirring speed was 900 r / min, and the time was 25 minutes; the high-speed dispersion speed in S3 was 1100 r / min, the time was 30 minutes, and the grinding was carried out 3 times; the vacuum degree in S4 was -0.08 MPa, and the defoaming time was 30 minutes.

[0077] Experimental Example 4 The following components were included: benzimidazolone yellow PY151 (15%), titanium nickel yellow PY53 (30%), polydimethylsiloxane (37%), modified polydimethylsiloxane (2.5%), fumed silica (1%), and silane coupling agent (0.5%).

[0078] The preparation steps were the same as in Experimental Example 1, and the parameters were adjusted as follows: the heating temperature in S2 was 43°C, the stirring speed was 850 r / min, and the time was 18 minutes; the high-speed dispersion speed in S3 was 1250 r / min, the time was 22 minutes, and the grinding was carried out 4 times; the vacuum degree in S4 was -0.09 MPa, and the defoaming time was 25 minutes.

[0079] Experimental Example 5 Comprise the following components: isoindoline yellow PY185 (35%), bismuth vanadate yellow PY184 (15%), vinyl silicone oil (36%), modified dimethicone (4.5%), fumed silica (2.5%), silane coupling agent (2%).

[0080] The preparation steps are the same as in Experimental Example 1, with the following parameters: in S2, the heating temperature is 50°C, the stirring speed is 1200 r / min, and the time is 30 minutes; in S3, the high-speed dispersion speed is 1400 r / min, the time is 35 minutes, and the grinding is 5 times; in S4, the vacuum degree is -0.1 MPa, and the defoaming time is 30 minutes.

[0081] Experimental Example 6 Comprise the following components: benzimidazolone yellow PY154 (25%), titanium chromium yellow PY162 (20%), polydimethylsiloxane (39%), modified dimethicone (3%), fumed silica (1.8%), silane coupling agent (1.2%).

[0082] The preparation steps are the same as in Experimental Example 1, with the following parameters: in S2, the heating temperature is 46°C, the stirring speed is 950 r / min, and the time is 20 minutes; in S3, the high-speed dispersion speed is 1150 r / min, the time is 25 minutes, and the grinding is 4 times; in S4, the vacuum degree is -0.085 MPa, and the defoaming time is 22 minutes.

[0083] Experimental Example 7 Comprise the following components: benzimidazolone yellow PY151 (12%), isoindoline yellow PY139 (8%), titanium nickel yellow PY53 (20%), polydimethylsiloxane (42%), modified dimethicone (3.2%), fumed silica (2%), silane coupling agent (0.8%).

[0084] The preparation steps are the same as in Experimental Example 1, with the following parameters: in S2, the heating temperature is 44°C, the stirring speed is 900 r / min, and the time is 22 minutes; in S3, the high-speed dispersion speed is 1180 r / min, the time is 28 minutes, and the grinding is 3 times; in S4, the vacuum degree is -0.08 MPa, and the defoaming time is 28 minutes.

[0085] Experimental Example 8 Benzimidazolone yellow PY175 (20%), titanium chromium yellow PY162 (10%), bismuth vanadate yellow PY184 (15%), vinyl silicone oil (40%), modified dimethicone (3.5%), fumed silica (2.2%), silane coupling agent (1.3%).

[0086] The preparation steps are the same as those in Experimental Example 1, and the parameters are adjusted as follows: the heating temperature in S2 is 47℃, the stirring speed is 1050r / min, and the time is 25 minutes; the high-speed dispersion speed in S3 is 1220r / min, the time is 30 minutes, and the grinding is 4 times; and the vacuum degree in S4 is-0.09MPa, and the defoaming time is 26 minutes.

[0087] Experimental Example 9 Benzimidazolone yellow PY154 (10%), isoindoline yellow PY185 (10%), titanium nickel yellow PY53 (10%), bismuth vanadate yellow PY184 (10%), a mixture of dimethicone and vinyl silicone oil (2:1, 41%), modified dimethicone (3.8%), fumed silica (2.5%), and silane coupling agent (1.7%).

[0088] The preparation steps are the same as those in Experimental Example 1, and the parameters are adjusted as follows: the heating temperature in S2 is 49℃, the stirring speed is 1100r / min, and the time is 28 minutes; the high-speed dispersion speed in S3 is 1350r / min, the time is 32 minutes, and the grinding is 5 times; and the vacuum degree in S4 is-0.095MPa, and the defoaming time is 30 minutes.

[0089] Comparative Example 1: A traditional chromium yellow silica gel color paste (PbCrO4, industrial grade) was used.

[0090] Comparative Example 2: A single organic pigment C.I. Pigment Yellow 154 silica gel color paste (industrial grade) was used.

[0091] The yellow silica gel color pastes obtained in Experimental Examples 1-9 and Comparative Examples 1-2 were tested for performance, and the test items and execution standards are as follows: the heavy metal content was detected according to the RoHS directive (2011 / 65 / EU); the fineness was determined according to the GB / T 1724-2019 standard; the tinting strength, weather resistance and compatibility were evaluated according to the relevant provisions of the Shanghai Enterprise Standard Q31 / 0120000242C001-2015; the heat resistance was tested according to the HG / T 3853-2006 standard; and the dispersion stability and storage stability were tested according to the GB / T 6753.3 standard. The results are shown in Table 1 below: Table 1

[0092] According to the results in the above table, the composite environmentally friendly yellow silica gel color paste prepared in the present application can replace or be superior to the traditional chromium yellow silica gel color paste in terms of tinting strength, heat resistance, weather resistance and dispersion stability, and is non-toxic and environmentally friendly, and does not contain any heavy metal elements.

[0093] Further, the composite yellow silica gel color paste prepared in the experimental example 1 is applied to a silicone sealant for building, and the color paste is added in an amount of 3%. The colored silicone sealant has bright color and good uniformity, does not change color at 300 DEG C, and has outdoor weather resistance of grade 7-8, meeting the environmental protection requirements.

[0094] The composite yellow silica gel color paste prepared in the experimental example 2 is applied to a liquid silicone rubber (LSR), and the color paste is added in an amount of 2.5%. The colored liquid silicone rubber product does not change color at 300 DEG C, has weather resistance of grade 7-8, is non-toxic and environmentally friendly, and passes the RoHS test.

[0095] The composite yellow silica gel color paste prepared in the experimental example 3 is applied to a silica gel leather coating, and the color paste is added in an amount of 5% and processed by a coating process. The colored silica gel leather has uniform color and good rubbing resistance, has outdoor weather resistance of grade 7-8, and meets the environmental protection standards (RoHS test).

[0096] In summary, the present application provides an environmentally friendly color paste for silica gel, which can solve the environmental pollution problem of heavy metals in traditional chromium yellow color paste by using an organic-inorganic composite strategy. The environmentally friendly organic pigments of benzimidazolone and isoindoline are compounded with titanium-based, bismuth-based and nickel-based inorganic pigments in a scientific ratio, which not only maintains the advantages of bright color and strong tinting strength of organic pigments, but also fully utilizes the characteristics of high heat resistance, strong hiding power and good weather resistance of inorganic pigments. The silicone-based dispersion medium and additives ensure the excellent compatibility and long-term stability of the color paste and the silica gel base material. The color paste has the outstanding advantages of no heavy metals, heat resistance of ≥300 DEG C, weather resistance of grade 7-8, excellent dispersion stability, etc., can replace harmful chromium yellow color paste, and is widely used in coloring of various silica gel products such as liquid silicone rubber, silicone building adhesive, electronic packaging adhesive, automobile sealant, etc. The preparation process is simple and easy to control, and is suitable for industrial production.

[0097] Obviously, those skilled in the art can make various modifications and variations to the present application without departing from the spirit and scope of the present application. Thus, if these modifications and variations of the present application fall within the scope of the claims of the present application and their equivalents, the present application is also intended to include these modifications and variations.

Claims

1. An environmentally friendly color paste for silica gel, characterized by: Calculated by mass percentage, it includes the following components: Organic pigments: 15% to 35%; Inorganic pigments: 15% to 30%; Silicone-based dispersion medium: 35% to 45%; Additives: 5% to 10%; The organic pigment is selected from at least one of benzimidazolone yellow pigments and isoindoline yellow pigments; the inorganic pigment is selected from at least one of titanium yellow pigments, bismuth yellow pigments and nickel yellow pigments.

2. The environmentally friendly color paste for silica gel according to claim 1, characterized in that: The organic pigment is at least one selected from benzimidazolone yellow PY154, benzimidazolone yellow PY151, benzimidazolone yellow PY175, isoindoline yellow PY139 and isoindoline yellow PY185.

3. The environmentally friendly color paste for silica gel according to claim 1, characterized in that: The inorganic pigment is selected from at least one of titanium nickel yellow PY53, titanium chrome yellow PY162 and bismuth vanadate yellow PY184.

4. The environmentally friendly color paste for silica gel according to claim 1, characterized in that: The silicone-based dispersion medium is selected from at least one of polydimethylsiloxane and vinyl silicone oil.

5. The environmentally friendly color paste for silica gel according to claim 1, characterized in that: The auxiliary agents include dispersants, thixotropic agents and stabilizers; The dispersant includes modified polydimethylsiloxane, the thixotropic agent includes fumed silica, and the stabilizer includes a silane coupling agent.

6. The environmentally friendly color paste for silica gel according to claim 1, characterized in that: The fineness of the color paste is not greater than 15 μm, and the heat-resistant temperature of the color paste is not lower than 300° C.

7. A method for preparing the environmentally friendly color paste for silica gel according to any one of claims 1 to 6, characterized in that: include: Drying the organic pigments and the inorganic pigments; mixing the silicone-based dispersion medium with the additive; Adding the pretreated pigment into the mixed dispersion system for dispersion and grinding; The ground color paste is degassed.

8. The preparation method according to claim 7, characterized in that: The drying treatment is carried out at a temperature of 80° C. to 100° C., and for a drying time of 4 to 6 hours.

9. The preparation method according to claim 7, characterized in that: The dispersion grinding includes high-speed dispersion and mechanical grinding, grinding until the fineness reaches less than 10 μm; The rotation speed of the high-speed dispersion is 1000-1500 r / min, and the time is 20-30 minutes; the mechanical grinding adopts a three-roller grinder or a basket sand mill to grind 3-5 times.

10. The preparation method according to claim 7, characterized in that: The degassing treatment is carried out under vacuum conditions with a vacuum degree of -0.08 to -0.1 MPa for 20 to 30 minutes.

11. Use of the environmentally friendly color paste for silica gel according to any one of claims 1 to 6 in silica gel coloring.

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