Environment-friendly color paste for silica gel, preparation method and application thereof

Abstract

The present application relates to the technical field of environment-friendly color paste, and provides an environment-friendly color paste for silica gel, a preparation method and application thereof.The color paste comprises, by mass percentage, 15-35% of organic pigment, 15-30% of inorganic pigment, 35-45% of silicone-based dispersion medium and 5-10% of auxiliary agent.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.Through the organic-inorganic composite strategy, the color paste has the advantages of bright color of organic pigment and high heat resistance and strong hiding power of inorganic pigment, and the comprehensive performance is optimized.The color paste has the characteristics of non-toxicity, environment-friendliness, high heat resistance, excellent dispersion stability and storage stability.

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 chromium 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:

[0010] Organic pigment: 15% to 35%;

[0011] Inorganic pigment: 15% to 30%;

[0012] Silicone-based dispersion medium: 35% to 45%;

[0013] Auxiliary agent: 5% to 10%;

[0014] The organic pigment is selected from at least one of benzimidazolone yellow pigment and isoindoline yellow pigment; the inorganic pigment is selected from at least one of titanium yellow pigment, bismuth yellow pigment and nickel yellow pigment.

[0015] 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.

[0016] Optionally, the inorganic pigment is selected from at least one of titanium-nickel yellow PY53, titanium-chromium yellow PY162 and bismuth vanadate yellow PY184.

[0017] Optionally, the silicone-based dispersion medium is selected from at least one of polydimethylsiloxane and vinyl silicone oil.

[0018] Optionally, the auxiliary agent comprises a dispersant, a thixotropic agent and a stabilizer.

[0019] The dispersant comprises modified polydimethylsiloxane, the thixotropic agent comprises fumed silica, and the stabilizer comprises a silane coupling agent.

[0020] Optionally, the fineness of the color paste is not greater than 15 μm, and the heat-resistant temperature of the color paste is not less than 300℃.

[0021] The present application further provides a preparation method of the above-mentioned environment-friendly color paste for silica gel, comprising:

[0022] Drying the organic pigment and the inorganic pigment;

[0023] Mixing the silicone-based dispersion medium with the auxiliary agent;

[0024] The pretreated pigment is added into the mixed dispersion system for dispersion grinding;

[0025] The ground color paste is subjected to defoaming treatment.

[0026] Optionally, the drying treatment is performed at 80-100 DEG C for 4-6 hours.

[0027] Optionally, the dispersion grinding comprises high-speed dispersion and mechanical grinding, and the grinding is performed to a fineness of less than 10 microns.

[0028] The high-speed dispersion is performed at a speed of 1000-1500 r / min for 20-30 minutes, and the mechanical grinding is performed 3-5 times by using a three-roller grinder or a basket sand mill.

[0029] Optionally, the defoaming treatment is performed under vacuum at a vacuum degree of -0.08 to -0.1 MPa for 20-30 minutes.

[0030] The application further provides application of the above-mentioned color paste for environment-friendly silica gel in coloring of silica gel.

[0031] Compared with the prior art, the color paste for environment-friendly silica gel is prepared by compounding design of organic pigment and inorganic pigment, and realizes an environment-friendly and non-toxic coloring scheme for silica gel. 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 coloring materials for silica gel.

[0032] 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 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 dispersion performance of the organic pigment and the inorganic pigment in the silicone-based medium, ensures that the prepared color paste has a fineness of less than 10 microns, has no sedimentation and stratification phenomenon within 6 months, and can provide persistent and stable coloring effect for silica gel products. DETAILED DESCRIPTION

[0033] The application will be described in more detail in the following, in which preferred embodiments of the application are indicated. It should be understood that a person 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 a broad knowledge for a person skilled in the art and not as a limitation of the application.

[0034] The application is described in more detail by way of example in the following paragraphs. The advantages and features of the application will be more apparent according to the following description.

[0035] Based on the inspiration of the present specification, the person skilled in the art can form new technical solutions by cross combination of different embodiments without causing technical contradictions, and such variations shall be considered to fall within the protection scope of the present application.

[0036] Embodiment one

[0037] The color paste for the environment-friendly 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: organic pigments 15% to 35%; inorganic pigments 15% to 30%; silicone-based dispersion medium 35% to 45%; and additives 5% to 10%.

[0038] The organic pigments are selected from at least one of benzimidazolone yellow pigments and isoindoline yellow pigments.

[0039] The benzimidazolone yellow pigments and isoindoline yellow pigments have the characteristics of bright color and strong tinting strength, can provide excellent yellow tone, and are completely free of heavy metal components, meeting the environmental protection requirements. The addition of such organic pigments solves the environmental pollution problem of traditional chromium yellow paste containing heavy metals such as lead and chromium.

[0040] 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.

[0041] The inorganic pigments are selected from at least one of titanium yellow pigments, bismuth yellow pigments and nickel yellow pigments.

[0042] The addition of inorganic pigments is mainly to improve the heat resistance, hiding power and weather resistance of the color paste. 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℃.

[0043] 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.

[0044] 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.

[0045] The embodiment of the present application has the advantages of both organic and inorganic pigments, i.e., the bright color and strong tinting strength of the organic pigment and the high heat resistance, strong hiding power and good weather resistance of the inorganic pigment, thereby obtaining a composite color paste with excellent comprehensive performance.

[0046] Further, the silicone-based dispersion medium plays a role in dispersing the pigment particles and providing fluidity, while ensuring good compatibility of the color paste with the silica gel base material.

[0047] The silicone-based dispersion medium is selected from at least one of polydimethylsiloxane and vinyl silicone oil.

[0048] The polydimethylsiloxane has excellent thermal stability and chemical inertness, and excellent compatibility with the silica gel system, and is preferably alpha, omega-dihydroxy polydimethylsiloxane; the vinyl silicone oil contains active vinyl groups and can participate in crosslinking reactions in some silica gel curing systems, further improving the compatibility.

[0049] In a specific example, the polydimethylsiloxane or the vinyl silicone oil can be used alone or mixed in a certain proportion, and preferably mixed in a mass ratio of 1:1 to obtain better comprehensive performance.

[0050] Specifically, the auxiliary agents include dispersants, thixotropic agents and stabilizers, and the synergistic effect of the three types of auxiliary agents is the key to ensuring excellent dispersion stability and storage stability of the color paste.

[0051] The dispersant includes modified polydimethylsiloxane.

[0052] The 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 the pigment particles and the dispersion medium and improve the dispersion effect of the pigment. This modification treatment makes the dispersant not only maintain good compatibility with the silicone-based dispersion medium, but also have excellent dispersion performance.

[0053] The thixotropic agent includes fumed silica.

[0054] The 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 pigment particles from settling when at rest, and improve the storage stability.

[0055] The stabilizer includes a silane coupling agent.

[0056] The silane coupling agent can form chemical bonding on the surface of the organic pigment, improve the binding force between the pigment and the silicone-based dispersion medium, and thus improve the dispersion stability. Meanwhile, the silane coupling agent can also improve the surface properties of the pigment particles and reduce the occurrence of agglomeration.

[0057] In a specific example, the fineness of the color paste is not greater than 15 pm, preferably not greater than 10 pm, and more preferably reaches 8 pm or less. The control of the fineness directly affects the coloring effect and appearance quality of the color paste. The smaller the fineness, the more uniform the coloring, and the better the gloss.

[0058] The heat resistance of the color paste is not less than 300℃. The heat resistance ensures that the color paste can meet the requirements of the silicone in high-temperature processing and use environment, and is an important performance requirement for replacing the medium-chromium yellow color paste.

[0059] Further, the environmentally friendly color paste for silicone provided by the embodiment of the present application has a wide application in coloring of silicone.

[0060] 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. Generally, an addition amount of 1% can obtain a lighter yellow color, and an addition amount of 5% 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.

[0061] 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.

[0062] 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.

[0063] 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.

[0064] In summary, the environment-friendly color paste for silica gel 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 tinting strength; 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 silica gel base material. The modified polydimethylsiloxane dispersant, fumed silica thixotropic agent and silane coupling agent stabilizer synergistically ensure excellent dispersion stability and storage stability. The environmental pollution problem of traditional chromium yellow paste containing heavy metals can be solved, and the key performance indicators such as tinting strength, heat resistance and weather resistance reach or exceed the level of traditional products, thereby providing an environment-friendly coloring solution for the silica gel industry.

[0065] Embodiment two

[0066] The embodiment also provides a preparation method of the environment-friendly color paste for silica gel, and the preparation method of the embodiment of the present application comprises the following steps:

[0067] S1, pigment pretreatment: dry treatment of organic pigments and inorganic pigments.

[0068] The pigments often contain 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.

[0069] The dry treatment condition is 80℃-100℃, and the dry time is 4-6 hours. Under this temperature and time condition, the water in the pigments can be effectively removed, and the structure and performance of the pigments 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.

[0070] 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.

[0071] S2, dispersion system preparation: mixing silicone-based dispersion medium and additives.

[0072] During the mixing process, the silicone-based dispersion medium can be heated to 40℃-50℃, which is beneficial to the dissolution and dispersion of the additives and improves the mixing efficiency. The selection of heating temperature should ensure that the additives can be fully dispersed, and the temperature should not be too high to cause the volatilization or decomposition of some components.

[0073] The mixing method can be mechanical stirring, and the stirring speed is usually 800-1000r / min, and the stirring time is 15-30 minutes, until the components are uniformly mixed.

[0074] S3, mixing and grinding: the pretreated pigment is added into the mixed dispersion system for dispersion grinding.

[0075] The dispersion grinding includes two stages of high-speed dispersion and mechanical grinding, and the grinding fineness is less than 10 μm.

[0076] The 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 the 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 the time should be moderate. If the rotation speed is too low, the dispersion effect is not good. If the rotation speed is too high, too many bubbles can be introduced. If the time is too short, the dispersion is not sufficient. If the time is too long, the temperature can be increased to affect the performance of the color paste.

[0077] The mechanical grinding stage: the mechanical grinding is performed 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 the relative movement of the three rollers. The basket sand mill can achieve fine dispersion of the pigment by the 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.

[0078] 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. The specific selection of equipment and adjustment of operating parameters belong to the usual means of those skilled in the art.

[0079] S4, stabilization treatment: the ground color paste is subjected to defoaming treatment.

[0080] During the grinding process, a certain amount of bubbles will inevitably be introduced. If these bubbles are not removed in time, they will affect the appearance and use performance of the color paste.

[0081] The defoaming treatment is performed under vacuum conditions, 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 bubbles, and at the same time will not cause adverse effects on other properties of the color paste. If the vacuum degree is too low, the defoaming effect is not good. If the vacuum degree is too high, some volatile components can be lost.

[0082] 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.

[0083] Through the above preparation process, an 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.

[0084] Example Three

[0085] The yellow silica gel color paste obtained in the following experimental examples 1-9 is subjected to performance testing by the present embodiment.

[0086] Experimental Example 1

[0087] 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%), silane coupling agent (0.5%).

[0088] Preparation steps:

[0089] S1: Dry benzimidazolone yellow PY154 and titanium nickel yellow PY53 at 85°C for 5 hours respectively;

[0090] S2: Heat the polydimethylsiloxane to 45°C, add the auxiliary, and stir at a speed of 800 r / min for 20 minutes;

[0091] S3: Gradually add the pretreated pigments to the dispersion system, high-speed disperse at a speed of 1200 r / min for 25 minutes, and then grind 4 times with a three-roll grinder, with fineness reaching 8 μm;

[0092] S4: Defoam under a vacuum degree of -0.09 MPa for 25 minutes.

[0093] Experimental Example 2

[0094] The following components are 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%).

[0095] The preparation steps are the same as in experimental example 1, with the following parameter adjustments: heating temperature in S2 is 48°C, stirring speed is 1000 r / min, and time is 15 minutes; high-speed dispersion speed in S3 is 1300 r / min, time is 20 minutes, and grinding is 5 times; vacuum degree in S4 is -0.1 MPa, and defoaming time is 20 minutes.

[0096] Experimental Example 3

[0097] The following components are included: benzimidazolone yellow PY175 (15%), isoindoline yellow PY185 (10%), bismuth vanadate yellow PY184 (10%), polydimethylsiloxane and vinyl silicone oil mixture (1:1, 35%), modified polydimethylsiloxane (3.5%), fumed silica (2%), and silane coupling agent (1.5%).

[0098] The preparation procedure is the same as that in Experimental Example 1, with the following parameters: the heating temperature in S2 is 42°C, the stirring speed is 900 r / min, and the time is 25 min; the high-speed dispersion speed in S3 is 1100 r / min, the time is 30 min, and the grinding is performed 3 times; and the vacuum degree in S4 is -0.08 MPa, and the defoaming time is 30 min.

[0099] Experimental Example 4

[0100] It comprises the following components: benzimidazolone yellow PY151 (15%), titanium nickel yellow PY53 (30%), polydimethylsiloxane (37%), modified polydimethylsiloxane (2.5%), fumed silica (1%), and silane coupling agent (0.5%).

[0101] The preparation procedure is the same as that in Experimental Example 1, with the following parameters: the heating temperature in S2 is 43°C, the stirring speed is 850 r / min, and the time is 18 min; the high-speed dispersion speed in S3 is 1250 r / min, the time is 22 min, and the grinding is performed 4 times; and the vacuum degree in S4 is -0.09 MPa, and the defoaming time is 25 min.

[0102] Experimental Example 5

[0103] It comprises the following components: isoindoline yellow PY185 (35%), bismuth vanadate yellow PY184 (15%), vinyl silicone oil (36%), modified polydimethylsiloxane (4.5%), fumed silica (2.5%), and silane coupling agent (2%).

[0104] The preparation procedure is the same as that in Experimental Example 1, with the following parameters: the heating temperature in S2 is 50°C, the stirring speed is 1200 r / min, and the time is 30 min; the high-speed dispersion speed in S3 is 1400 r / min, the time is 35 min, and the grinding is performed 5 times; and the vacuum degree in S4 is -0.1 MPa, and the defoaming time is 30 min.

[0105] Experimental Example 6

[0106] It comprises the following components: benzimidazolone yellow PY154 (25%), titanium chromium yellow PY162 (20%), polydimethylsiloxane (39%), modified polydimethylsiloxane (3%), fumed silica (1.8%), and silane coupling agent (1.2%).

[0107] The preparation procedure is the same as that in Experimental Example 1, with the following parameters: the heating temperature in S2 is 46°C, the stirring speed is 950 r / min, and the time is 20 min; the high-speed dispersion speed in S3 is 1150 r / min, the time is 25 min, and the grinding is performed 4 times; and the vacuum degree in S4 is -0.085 MPa, and the defoaming time is 22 min.

[0108] Experimental Example 7

[0109] The following components are included: benzimidazolone yellow PY151 (12%), isoindoline yellow PY139 (8%), titanium nickel yellow PY53 (20%), dimethicone (42%), modified dimethicone (3.2%), fumed silica (2%), silane coupling agent (0.8%).

[0110] The preparation procedure is the same as in Experimental Example 1, with the following parameters: heating temperature in S2 is 44°C, stirring speed is 900 r / min, and time is 22 minutes; high-speed dispersion speed in S3 is 1180 r / min, time is 28 minutes, and grinding is performed 3 times; vacuum degree in S4 is -0.08 MPa, and defoaming time is 28 minutes.

[0111] Experimental Example 8

[0112] 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%).

[0113] The preparation procedure is the same as in Experimental Example 1, with the following parameters: heating temperature in S2 is 47°C, stirring speed is 1050 r / min, and time is 25 minutes; high-speed dispersion speed in S3 is 1220 r / min, time is 30 minutes, and grinding is performed 4 times; vacuum degree in S4 is -0.09 MPa, and defoaming time is 26 minutes.

[0114] Experimental Example 9

[0115] Benzimidazolone yellow PY154 (10%), isoindoline yellow PY185 (10%), titanium nickel yellow PY53 (10%), bismuth vanadate yellow PY184 (10%), mixture of dimethicone and vinyl silicone oil (2:1, 41%), modified dimethicone (3.8%), fumed silica (2.5%), silane coupling agent (1.7%).

[0116] The preparation procedure is the same as in Experimental Example 1, with the following parameters: heating temperature in S2 is 49°C, stirring speed is 1100 r / min, and time is 28 minutes; high-speed dispersion speed in S3 is 1350 r / min, time is 32 minutes, and grinding is performed 5 times; vacuum degree in S4 is -0.095 MPa, and defoaming time is 30 minutes.

[0117] Comparative Example 1, traditional chromium yellow silicone color paste (PbCr04, industrial grade) is used.

[0118] Comparative Example 2, single organic pigment C.I. Pigment Yellow 154 silicone color paste (industrial grade) is used.

[0119] The yellow silica gel color paste obtained in Experimental Example 1-9 and Comparative Examples 1-2 is subjected to performance testing, and the test items and execution standards are as follows: the heavy metal content is detected according to the RoHS directive (2011 / 65 / EU); the fineness is determined according to the GB / T 1724-2019 standard; the tinting strength, weather resistance and compatibility are evaluated according to the relevant provisions of the Shanghai Enterprise Standard Q31 / 0120000242C001-2015; the heat resistance is tested according to the HG / T 3853-2006 standard; and the dispersion stability and storage stability are tested according to the GB / T 6753.3 standard. The results are shown in Table 1 below:

[0120] Table 1

[0121]

[0122] According to the results in the above table, the composite environmentally friendly yellow silica gel color paste prepared in the application can replace or be superior to 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.

[0123] Further, the composite yellow silica gel color paste prepared in Experimental Example 1 is applied to a silicone sealant for building, and the color paste addition amount is 3%. The colored silicone sealant has bright color and good uniformity, does not change color at 300°C, and has outdoor weather resistance of 7-8 levels, meeting the environmental protection requirements.

[0124] The composite yellow silica gel color paste prepared in Experimental Example 2 is applied to a liquid silicone rubber (LSR), and the color paste addition amount is 2.5%. The colored liquid silicone rubber product does not change color at 300°C, has weather resistance of 7-8 levels, is non-toxic and environmentally friendly, and passes the RoHS detection.

[0125] The composite yellow silica gel color paste prepared in Experimental Example 3 is applied to a silicone leather coating, and the color paste addition amount is 5%. The colored silicone leather has uniform color and good friction resistance, has outdoor weather resistance of 7-8 levels, and meets the environmental protection standards (RoHS detection).

[0126] In summary, the present application provides an environment-friendly color paste for silica gel, which can solve the environmental pollution problem of traditional chromium yellow paste containing heavy metals through organic-inorganic composite strategy. The benzimidazolone and isoindoline environment-friendly organic pigments are scientifically compounded with titanium, bismuth and nickel inorganic pigments, which not only maintains the advantages of bright color and strong coloring power of organic pigments, but also fully utilizes the characteristics of high heat resistance, strong hiding power and good weather resistance of inorganic pigments. Through silicone-based dispersion medium and additives, the excellent compatibility and long-term stability of the color paste and silica gel base material are ensured. The color paste has the outstanding advantages of completely no heavy metals, heat resistance ≥ 300 DEG C, weather resistance up to 7-8 levels, excellent dispersion stability, etc., can replace harmful chromium yellow paste, and is widely applied to 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.

[0127] 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 belong to the scope of the claims of the present application and their equivalent technologies, the present application also intends to include these modifications and variations.

Claims

1. An environmentally friendly colorant for silicone, characterized in that: By mass percentage, it comprises the following components: Organic pigment: 15%~35%; Inorganic pigment: 15%~30%; Silicone-based dispersion medium: 35%~45%; Auxiliary agent: 5%~10%; The organic pigment is selected from at least one of benzimidazolone yellow pigment and isoindoline yellow pigment; the inorganic pigment is selected from at least one of titanium yellow pigment, bismuth yellow pigment and nickel yellow pigment; The auxiliary agent comprises dispersant, thixotropic agent and stabilizer; The dispersant comprises modified polydimethylsiloxane, the thixotropic agent comprises fumed silica, and the stabilizer comprises silane coupling agent; The fineness of the color paste is not more than 10 μm, and the heat-resistant temperature of the color paste is not less than 300 ℃, without sedimentation stratification phenomenon within 6 months.

2. The eco-friendly color paste for silica gel according to claim 1, characterized in that: 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.

3. The eco-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 chromium yellow PY162 and bismuth vanadate yellow PY184.

4. The eco-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. A method for preparing the color paste for the environmentally friendly silica gel according to any one of claims 1 to 4, characterized in that, It comprises: The organic pigment and the inorganic pigment are subjected to drying treatment; The silicone-based dispersion medium is mixed with the auxiliary agent; The pretreated pigment is added into the mixed dispersion system for dispersion grinding; The ground color paste is subjected to defoaming treatment.

6. The method of claim 5, wherein: The drying treatment is performed at 80 ℃~100 ℃, and the drying time is 4~6 hours.

7. The method of claim 5, wherein: The dispersion grinding comprises high-speed dispersion and mechanical grinding, and the grinding is performed to a fineness of 10 μm or less; The high-speed dispersion is performed at a rotation speed of 1000~1500 r / min for 20~30 minutes; the mechanical grinding is performed for 3~5 times by using a three-roll grinder or a basket sand mill.

8. The method of claim 5, wherein: The defoaming treatment is performed under vacuum condition, the vacuum degree is-0.08~-0.1 MPa, and the time is 20~30 minutes.

9. Application of the environment-friendly color paste for silica gel in coloring of silica gel.

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