A CPVC adhesive as well as a preparation method and application thereof

Abstract

This invention discloses a CPVC adhesive, its preparation method, and its application. The CPVC adhesive comprises the following components by weight percentage: 8-12% chlorinated polyvinyl chloride resin, 20-25% first main solvent, 28-35% second main solvent, 25-35% co-solvent, 0.1-0.5% thickener, 5-7% auxiliary resin, 0.02-0.3% stabilizer, and 0.1-0.3% colorant; the first main solvent is cyclohexanone; the second main solvent is tetrahydrofuran; the thickener is styrene-acrylonitrile copolymer; the intrinsic viscosity of the styrene-acrylonitrile copolymer is 8-10 dL / g; and the viscosity of the CPVC adhesive at 25°C is above 1000 cps. The CPVC adhesive provided by this invention effectively improves the problem of decreased compatibility and adhesion caused by the introduction of color powder by adding an appropriate amount of styrene-acrylonitrile copolymer as a thickener. This allows the CPVC adhesive to achieve rich colors while still having excellent adhesion and storage stability.

Description

Technical Field

[0001] This application belongs to the field of adhesive technology, and more specifically, relates to a CPVC adhesive, its preparation method and application. Background Technology

[0002] CPVC solvent-based adhesives have been used in industry for over twenty years. Their bonding mechanism primarily relies on the solvent's dissolution and swelling of the substrate surface, followed by molecular-level interfacial bonding after the solvent evaporates. Traditionally, these adhesives were mostly colorless, but with the continuous expansion of applications, various color types have now been developed. The introduction of color not only helps users distinguish between different types or uses of adhesives—for example, IPS Corporation in the United States uses color to identify different product series of CPVC adhesives—but also provides significant visual assistance during construction, allowing construction workers to more quickly and easily identify whether adhesive has been applied and whether the amount of adhesive used is appropriate. In addition, color markings also facilitate the identification of old adhesive residue. When the bonded surface detaches and re-adhesion is required, users can clearly see the adhesive marks and easily determine whether the adhesive marks have been completely removed, improving the effect of secondary adhesive application. However, the addition of pigments or color powders can disrupt the homogeneity and compatibility of the adhesive system, thereby affecting its bonding performance and storage stability. Currently, the bonding performance and storage stability of existing colored CPVC adhesive products on the market still need further improvement.

[0003] Therefore, it is particularly important to develop a colored CPVC adhesive that combines excellent bonding properties and storage stability. Summary of the Invention

[0004] The primary objective of this invention is to overcome the defects or shortcomings of existing colored CPVC adhesives and to provide a colored CPVC adhesive.

[0005] Another object of the present invention is to provide a method for preparing the above-mentioned CPVC adhesive.

[0006] Another object of the present invention is to provide the application of the above-mentioned CPVC adhesive.

[0007] To achieve the above objectives, the present invention is implemented through the following technical solution: A CPVC adhesive comprising the following components by weight percentage: Chlorinated polyvinyl chloride resin 8~12%; Primary solvent 20-25%; The second primary solvent is 28-35%; Cosolvent 25-35%; Thickener 0.1~0.5%; Auxiliary resin 5~7%; Stabilizer 0.02~0.3%; Pigment 0.1~0.3%; The first primary solvent is cyclohexanone; The second primary solvent is tetrahydrofuran; The thickener is a styrene-acrylonitrile copolymer; The intrinsic viscosity of the styrene-acrylonitrile copolymer is 8~10 dL / g; The CPVC adhesive has a viscosity of over 1000 cps at 25°C.

[0008] The inventors discovered that using a styrene-acrylonitrile copolymer with an intrinsic viscosity of 8-10 dL / g as a thickener in CPVC adhesives can improve the compatibility and adhesion performance degradation caused by the introduction of colorants, resulting in colored CPVC adhesives with both excellent adhesion and storage stability. This is due to the presence of polar groups in the styrene-acrylonitrile copolymer, which can coordinate with the chloropropyl groups in the chlorinated polyvinyl chloride resin. Simultaneously, its non-polar segments physically bind with the chlorinated polyvinyl chloride resin through van der Waals forces, forming a stable three-dimensional network structure in the adhesive and effectively improving its adhesion performance. Furthermore, the presence of cyano groups in the styrene-acrylonitrile copolymer enhances the compatibility between the adhesive and colorants, improving the dispersion stability of the colorants in the system.

[0009] While the storage stability of CPVC adhesive is improved with the increase of styrene-acrylonitrile copolymer content, its adhesive performance will decrease accordingly.

[0010] Preferably, in the CPVC adhesive, the amount of the thickener is 0.2~0.4%.

[0011] It should be noted that the styrene-acrylonitrile copolymer described in this application can be a commercially available styrene-acrylonitrile copolymer, such as ADX-310, ADX-320, etc. It can also be prepared in-house using methods from the prior art, and no limitation is made herein.

[0012] The intrinsic viscosity test method can refer to ISO 1628-5 standard. The specific test method is as follows: use an Ubbelohde viscometer to determine the intrinsic viscosity, the test temperature is 25±0.01℃, the test solvent is methyl ethyl ketone (MEK), and the sample concentration is 0.005 g / mL.

[0013] As is known to those skilled in the art, while lower viscosity in CPVC adhesives helps improve solubility, bond strength, and quick-drying properties, it also significantly increases the risk of stress corrosion cracking in the substrate. Conversely, excessively high viscosity leads to difficulty in dissolution, which is detrimental to practical application. Furthermore, the inventors discovered that when the viscosity of the CPVC adhesive is below 1000 cps, the added colorant will rapidly precipitate due to insufficient support within the system, and even the subsequent addition of a thickener is insufficient to effectively improve its dispersibility and compatibility. In CPVC adhesives, the viscosity can be controlled by adjusting the proportions of the first main solvent, the second main solvent, and the co-solvent.

[0014] Preferably, the viscosity of the CPVC adhesive at 25°C is 1000~2500 cps.

[0015] More preferably, the viscosity of the CPVC adhesive at 25°C is 1200~2000 cps.

[0016] Preferably, the K value of the chlorinated polyvinyl chloride resin is 55-68.

[0017] Specifically, the chlorinated polyvinyl chloride resin can be a commercially available product, such as Shandong Gaoxin Chemical Co., Ltd.'s J-700, Hanwha GC, and Jung Yeon GC.

[0018] Preferably, the co-solvent can be a co-solvent commonly used in the art, such as one or more of acetone, butanone, or methyl isobutyl ketone.

[0019] More preferably, the co-solvent is acetone and butanone.

[0020] In CPVC adhesives, the solid content and solubility of the adhesive can be adjusted by adding auxiliary resins. These auxiliary resins can be commonly used in the art, such as acrylic resins or vinyl chloride resins. Those skilled in the art know that if the molecular weight of the auxiliary resin is too high, it will lead to dissolution difficulties, which is detrimental to the actual application of the adhesive; if its molecular weight is too low, it cannot effectively adjust the solid content of the adhesive. Therefore, acrylic resins with a molecular weight of 30,000~50,000 g / mol or vinyl chloride resins with a K value of 45~50 are typically selected. The acrylic resins can be commercially available products, such as Mitsubishi BR-116, Lucite 2013, and Lucite 2046. The vinyl chloride resins can be commercially available products, such as Hanwha CP430 and Hanwha TP400.

[0021] Preferably, the pigment is one or more of carbon black, titanium dioxide, permanent red, or benzimidazole yellow.

[0022] The stabilizer described in this invention can be any stabilizer commonly used in the prior art. For example, but not limited to, one or more of organotin stabilizers, calcium salt stabilizers, zinc salt stabilizers, antioxidants, or epoxidized soybean oil.

[0023] Specifically, the organotin stabilizer is one or more of methyl mercaptan, di-n-octyltin dilaurate, octyltin maleate, or dibutyltin dilaurate.

[0024] Specifically, the calcium salt stabilizer is one or more of calcium stearate, calcium palmitate, calcium laurate, calcium benzoate, and calcium dodecylbenzene sulfonate.

[0025] Specifically, the zinc salt stabilizer is one or more of zinc stearate, zinc palmitate, zinc laurate, zinc benzoate, and zinc dodecylbenzenesulfonate.

[0026] The preparation method of the above-mentioned CPVC adhesive is also within the scope of protection of this invention, which includes the following steps: mixing and stirring chlorinated polyvinyl chloride resin, first main solvent, second main solvent, co-solvent, thickener, auxiliary resin, stabilizer and color powder evenly to obtain the CPVC adhesive.

[0027] Preferably, the stirring temperature is 40~50℃.

[0028] Preferably, the stirring time is 6-8 hours.

[0029] The application of the above-mentioned CPVC adhesive in bonding CPVC pipes is also within the scope of protection of this invention.

[0030] Compared with the prior art, the present invention has the following beneficial effects: This invention provides a colored CPVC adhesive. By using a styrene-acrylonitrile copolymer as a thickener in the CPVC adhesive, the problems of compatibility and decreased adhesive performance caused by the introduction of colorant are unexpectedly solved. The resulting colored CPVC adhesive exhibits both excellent adhesive performance and storage stability. Detailed Implementation

[0031] The present invention will be further described below with reference to embodiments and comparative examples. These embodiments are merely typical descriptions of the present invention, but the present invention is not limited thereto. Unless otherwise specified, the test methods used in the following embodiments and comparative examples are conventional methods, and the raw materials and reagents used are commercially available from conventional commercial sources.

[0032] Raw materials used in each embodiment and comparative example: Chlorinated polyvinyl chloride resin: J-700, Shandong Gaoxin Company, K value 55-68; Primary solvent: Cyclohexanone, Guangdong Guangshi Reagent Technology Co., Ltd.; Second primary solvent: Tetrahydrofuran, Guangdong Guangshi Reagent Technology Co., Ltd.; Cosolvent 1: Butanone, Guangdong Guangshi Reagent Technology Co., Ltd.; Cosolvent 2: Acetone, Guangdong Guangshi Reagent Technology Co., Ltd.; Thickener 1: Styrene-acrylonitrile copolymer, Jinchangshu Company, intrinsic viscosity is 8~10 dL / g; Thickener 2: Ethyl cellulose, a cellulose-based thickener, brand name HS30000YP2, Clariant Corporation; Thickener 3: Polyvinyl alcohol, brand name PVA1788, Wuhan Runxingyuan Technology Co., Ltd.; Thickener 4: Styrene-acrylonitrile copolymer, Jinchangshu Company, intrinsic viscosity is 5~6 dL / g; Thickener 5: Styrene-acrylonitrile copolymer, Jinchangshu Company, intrinsic viscosity is 12~14 dL / g; Stabilizer: Thiol methyltin heat stabilizer, Hubei Benxing Company; Auxiliary resin: Acrylic resin, BR-116, Mitsubishi Corporation, Japan; Pigment 1: Titanium dioxide, Guangzhou Huihe Pigment Co., Ltd.; Pigment 2: Permanent Red, Guangzhou Huihe Pigment Co., Ltd.; Pigment 3: Benzimidazole Yellow, Guangzhou Huihe Pigment Co., Ltd.; The same reagents were used in parallel experiments of all embodiments and comparative examples of this invention.

[0033] Examples 1-8 In Examples 1-8, the CPVC adhesive is prepared by the following method, including the following steps: S1. Weigh out the chlorinated polyvinyl chloride resin, the first main solvent, the second main solvent, the co-solvent, and the auxiliary resin according to the formula, and stir to mix; S2. Weigh the thickener, stabilizer and color powder according to the formula, add them to the system in step S1 and stir to mix. Heat to 48°C and stir for 6.5 hours to obtain the CPVC adhesive.

[0034] The specific formulations of Examples 1-8 are shown in Table 1. The viscosities of the CPVC adhesives prepared in Examples 1-8 are shown in Table 3.

[0035] Table 1. Detailed formulation of Examples 1-8 (unit: g)

[0036] Comparative Examples 1-7 Comparative Examples 1-7 provided different CPVC adhesives, differing from Example 1 only in their formulations, as shown in Table 2. The viscosities of the CPVC adhesives prepared in Comparative Examples 1-7 are shown in Table 3.

[0037] Table 2. Detailed formulation of Comparative Examples 1-7 (unit: g)

[0038] Comparative Example 8 This comparative example provides a CPVC adhesive, purchased from IPS Corporation, USA, with the grade: 550.

[0039] Performance testing (1) Viscosity test Viscosity tests were conducted on the CPVC adhesives prepared in each embodiment and comparative example, and the test results are shown in Table 3. The specific test method was as follows: testing was performed using a SmartL low-range viscometer at 25°C.

[0040] (2) Storage stability test The CPVC adhesives prepared in each embodiment and comparative example were tested for storage stability, and the test results are shown in Table 3. The specific test method was as follows: the CPVC adhesive was placed in a clean conical flask, sealed and stored at room temperature without exposure to direct sunlight, and the presence of stratification or powder flocculation was observed daily. If no such changes occurred within 30 days, the adhesive was deemed to have passed the storage stability test.

[0041] (3) Bond strength test The adhesive strength of the CPVC adhesives prepared in each embodiment and comparative example was tested, and the test results are shown in Table 3. The specific test method was as follows: Appropriate amounts of CPVC adhesive were taken and subjected to adhesive strength tests at 2h, 16h, and 72h according to QB / T2568-2002 "Soluble-based adhesives for rigid polyvinyl chloride (PVC-U) plastic pipe systems" to characterize the adhesive strength.

[0042] Table 3 Test results of the CPVC adhesives prepared in Examples 1-8 and Comparative Examples 1-8

[0043] As can be seen from Table 3, by adding a styrene-acrylonitrile copolymer with a characteristic viscosity of 8~10 dL / g, the present invention can effectively improve the compatibility problem of pigments, so that the prepared CPVC adhesive also has good storage stability and bonding strength, and its 72h bonding strength can reach more than 6.7 MPa.

[0044] Comparing Example 1 with Comparative Examples 1-3, it can be seen that when other types of thickeners are used or no thickener is added, the compatibility problem of the pigment cannot be effectively improved, resulting in it failing the storage stability test.

[0045] Comparing Example 1 and Comparative Examples 4-5, it can be seen that only by using a styrene-acrylonitrile copolymer with an intrinsic viscosity of 8-10 dL / g as a thickener can excellent adhesive properties be maintained while improving storage stability.

[0046] As can be seen from Comparative Example 6, when the viscosity of CPVC adhesive is below 1000 cps, the added pigment will quickly precipitate due to insufficient support in the system. Even with the addition of styrene-acrylonitrile copolymer with a characteristic viscosity of 8~10 dL / g, it is difficult to effectively improve the dispersibility and compatibility of the pigment and enhance its storage stability.

[0047] As can be seen from Comparative Example 7, the bonding strength of the prepared CPVC adhesive decreases with the increase of the amount of styrene-acrylonitrile copolymer added.

[0048] The specific embodiments of the present invention have been described above. It should be understood that the present invention is not limited to the specific embodiments described above, and those skilled in the art can make various modifications or variations within the scope of the claims, which do not affect the essence of the present invention.

Claims

1. A CPVC adhesive, characterized by, Includes the following components by weight percentage: Chlorinated polyvinyl chloride resin 8~12%; Primary solvent 20-25%; The second primary solvent is 28-35%; Cosolvent 25-35%; Thickener 0.1~0.5%; Auxiliary resin 5~7%; Stabilizer 0.02~0.3%; Pigment 0.1~0.3%; The first primary solvent is cyclohexanone; The second primary solvent is tetrahydrofuran; The thickener is a styrene-acrylonitrile copolymer; The intrinsic viscosity of the styrene-acrylonitrile copolymer is 8~10 dL / g; The CPVC adhesive has a viscosity of over 1000 cps at 25°C.

2. The CPVC adhesive according to claim 1, characterized in that, The amount of the thickener used is 0.2~0.4%.

3. The CPVC adhesive according to claim 1, characterized in that, The K value of the chlorinated polyvinyl chloride resin is 55~68.

4. The CPVC adhesive according to claim 1, characterized in that, The co-solvent is one or more of acetone, butanone, or methyl isobutyl ketone.

5. The CPVC adhesive according to claim 1, characterized in that, The pigment is one or more of carbon black, titanium dioxide, permanent red, or benzimidazole yellow.

6. The CPVC adhesive according to claim 1, characterized in that, The auxiliary resin is one or both of acrylic resin and vinyl chloride resin.

7. The CPVC adhesive according to claim 1, characterized in that, The stabilizer is one or more of organotin stabilizers, calcium salt stabilizers, zinc salt stabilizers, antioxidants, or epoxidized soybean oil.

8. A method for preparing the CPVC adhesive according to any one of claims 1 to 7, characterized in that, The process includes the following steps: mixing and stirring chlorinated polyvinyl chloride resin, a first main solvent, a second main solvent, a co-solvent, a thickener, an auxiliary resin, a stabilizer, and a colorant until homogeneous to obtain the CPVC adhesive.

9. The preparation method according to claim 8, characterized in that, The stirring temperature is 40~50℃.

10. The use of the CPVC adhesive according to any one of claims 1 to 7 in bonding CPVC pipes.

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