A method for preparing solvent-free water-soluble chlorinated polypropylene

Abstract

The present invention belongs to the technical field of water-soluble chlorinated polypropylene, and specifically discloses a method for preparing solvent-free water-soluble chlorinated polypropylene. After chlorinated polypropylene, acrylic acid / ester mixture (acrylic acid, methacrylic acid, butyl acrylate, octyl acrylate, methyl methacrylate), terminal hydroxyl hyperbranched polyester and cosolvent are uniformly mixed, an initiator is used to initiate chlorinated polypropylene to generate free radicals, and the acrylic acid / ester mixture is further initiated to carry out graft free radical polymerization, and then after amine neutralization, emulsification and deionized water dilution, solvent-free water-soluble chlorinated polypropylene with a solid content of 32-40% can be obtained. The process of the present invention is simple and easy to industrialize. The product has the advantages of low VOC content, no organic solvent, water dilution, excellent stability, etc., and is expected to be widely used in the fields of water-soluble coatings, non-polar or weakly polar plastic surface modification, etc.

Description

Technical Field

[0001] The invention relates to the technical field of water-soluble chlorinated polypropylene, and in particular to a method for preparing solvent-free water-soluble chlorinated polypropylene. Background Art

[0002] Water-soluble paint is a paint with water-soluble resin as the base material and water as the solvent. Water-soluble paint has the advantages of low carbon, energy saving, green, environmental protection and other environmentally friendly features, and is widely used in the fields of construction, automobile, light industry, chemical industry, machinery manufacturing, etc. In accordance with the requirements of the "dual carbon" emission targets and the urgent need for environmental protection, water-soluble paint continues to replace traditional solvent-based paints, and the market demand is gradually increasing.

[0003] Among the existing water-soluble coatings, water-soluble epoxy resins, water-soluble acrylic resins, water-soluble polyurethane resins, water-soluble urea-formaldehyde resins, etc. occupy the main market, but their polarity is relatively high, and their adhesion on the surface of non-polar plastics such as polypropylene and polyethylene is low, making it difficult to be used for the primer of polypropylene automobile bumpers. At present, the primer of domestic automobile bumper surface coating mainly adopts oily chlorinated polypropylene, and its solid content is only 8-10%. A large amount of organic solvents are volatilized during spraying and manufacturing, which seriously pollutes the environment and affects human health. Therefore, it is urgent to develop water-soluble chlorinated polypropylene to replace solvent-based chlorinated polypropylene to solve this environmental pollution problem. The existing foreign production technology of water-soluble chlorinated polypropylene is mainly completed by coating chlorinated polypropylene with emulsifier under high-speed stirring conditions. The stirring speed of the emulsifier is usually between 1200-3000rpm, with high speed and long time, high requirements on the reactor, small size of the reactor for a single batch, small industrial scale, high cost, low solid content (≤30%), and the market price of the product is about 100,000-200,000 yuan / ton, which is difficult to promote and use on a large scale. There are also some technical reports in China on the use of acrylic acid and acrylate grafted modified chlorinated polypropylene to prepare water-soluble chlorinated polypropylene, but a large amount of organic solvents such as toluene and dimethyl ester need to be added during the preparation process. Although the prepared product is water-soluble, the process of removing the organic solvent is complicated and difficult to remove completely. Products containing organic solvents have poor stability, pollute the environment during the drying process, and affect the health of construction workers. Therefore, the development of a synthesis technology for water-soluble chlorinated polypropylene that does not use organic solvents, has a simple process, is non-volatile, non-polluting, and low-cost is a fundamental way to solve the current problems in this field. Summary of the invention

[0004] In order to solve the deficiencies in the prior art, the present invention provides a method for preparing solvent-free water-soluble chlorinated polypropylene.

[0005] The present invention solves the above technical problems with the following technical solutions:

[0006] A method for preparing solvent-free water-soluble chlorinated polypropylene, the specific process of which is as follows:

[0007] (1) mixing chlorinated polypropylene, a portion of the acrylic acid / ester mixture, a terminal hydroxyl hyperbranched polyester and a cosolvent, gradually heating to about 80° C., and gradually dissolving the chlorinated polypropylene into a homogeneous solution under stirring;

[0008] (2) After dissolution, the temperature is lowered to 60-75° C., and the initiator and the remaining acrylic acid / ester mixture are gradually added to the solution of step (1). After the addition is completed, the mixture is stirred and reacted at 70-140° C. for 0.5-2 hours;

[0009] (3) cooling the mixture to 70-85° C., adding an amine neutralizer to neutralize the mixture to a pH value of 6.8-7.5, and then gradually adding an aqueous solution of an emulsifier, emulsifying the mixture for 0.5-3 hours at a stirring rate of 300-800 rpm, and adding deionized water to dilute the mixture and adjust the solid content, thereby obtaining solvent-free water-soluble chlorinated polypropylene;

[0010] The acrylic acid / ester mixture is a mixture of acrylic acid, methacrylic acid, butyl acrylate, octyl acrylate and methyl methacrylate.

[0011] Preferably, the solid content of the solvent-free water-soluble chlorinated polypropylene is 32-40%.

[0012] Preferably, the mass ratio of the chlorinated polypropylene, acrylic acid / ester mixture, terminal hydroxyl hyperbranched polyester and cosolvent is 100:(50-300):(0.5-3.0):(0.5-5.0), and most preferably is 100:(50-300):(0.5-3.0):(2.0-5.0).

[0013] More preferably, the mass ratio of acrylic acid, methacrylic acid, butyl acrylate, octyl acrylate and methyl methacrylate is 1: (0.5-1.0): (0.5-2.0): (0.5-2.5): (0.5-1.75).

[0014] Preferably, the hydroxyl-terminated hyperbranched polyester is one or more of HyPer H101, HyPer H102, HyPer H103, HyPer H201, HyPer H202 and HyPer H203 of Wuhan Hyperbranched Resin Technology Co., Ltd., and the number average molecular weight of the hydroxyl-terminated hyperbranched polyester is 500-2600 g / mol, and the hydroxyl value is 500-670 mgKOH / g. Their properties are shown in Table 1.

[0015] Table 1 Properties of hydroxyl-terminated hyperbranched polyesters

[0016] Product Name Hydroxyl value, mgKOH / g Number average molecular weight, g / mol HyPer H101 670 500 HyPer H102 600 1100 HyPer H103 560 2400 HyPer H201 550 600 HyPer H202 520 1200 HyPer H203 500 2600

[0017] Preferably, the chlorinated polypropylene in step (1) is one or more chlorinated polypropylenes having a chlorine content of 23-41%; more preferably, the products of Luzhou North Chemical Industry Co., Ltd., and their properties are shown in Table 2.

[0018] Table 2 Properties of chlorinated polypropylene

[0019] Product Name Chlorine content, % K33 25±2 K11 30±2 CP-20 25±2 CP-30 39±2 CK-800 31±2

[0020] Preferably, the cosolvent in step (1) is one or more of propylene glycol methyl ether, propylene glycol ethyl ether, propylene glycol butyl ether, ethylene glycol methyl ether, ethylene glycol ethyl ether, ethylene glycol butyl ether, and diethylene glycol dimethyl ether.

[0021] Preferably, the initiator is dibenzoyl peroxide (BPO), azobisisobutyl cyanide

[0022] One or more of tert-butyl peroxide (AIBN), tert-butyl peroxide 2-ethylhexanoate (TBPO), lauroyl peroxide (LPO), 1,1-bis(tert-amyl peroxy)cycloalkane, 1,1-bis(tert-amyl peroxy)-3,3,5-trimethylcyclohexane, dicumyl peroxide (DCP), tert-amyl peroxyacetate (TAPA), and tert-amyl peroxybenzoate (TAPB), with the usage amount being 0.1% to 0.5% of the mass of the chlorinated polypropylene in step (1).

[0023] Preferably, the emulsifier is one or more of dioctyl sodium sulfosuccinate, sodium dodecyl polyoxyethylene ether sulfate, sodium dodecyl sulfonate, sodium hexadecyl sulfonate and sodium dodecylbenzene sulfonate, and the amount used is 2%-10% of the mass of the chlorinated polypropylene in step (1).

[0024] Preferably, the amine neutralizing agent is one or more of triethanolamine, diethanolamine, methyldiethanolamine, N,N-dimethylethanolamine, triethylamine, and ammonia water.

[0025] The solvent-free water-soluble chlorinated polypropylene prepared by the present invention has the following advantages compared with the products of the prior art:

[0026] (1) The hydroxyl-terminated hyperbranched polyester has an ellipsoidal topological structure, which can effectively penetrate into the molecular weight of chlorinated polypropylene and promote the dissolution of chlorinated polypropylene, effectively avoiding the need to add organic solvents to dissolve chlorinated polypropylene in the prior art, which not only reduces the VOC content and organic solvent pollution, but also reduces the cumbersome process of removing organic solvents, thereby reducing production costs;

[0027] (2) The terminal hydroxyl hyperbranched polyester can effectively embed and disperse the chlorinated polypropylene modified by acrylic acid / ester grafting. The large number of polar hydroxyl groups on the surface are helpful for emulsification and water dispersion, thereby forming a stable water-soluble chlorinated polypropylene;

[0028] (3) During the drying or curing process, the hydroxyl groups of the terminal hydroxyl hyperbranched polyester can form hydrogen bonds and esterification reactions with the carboxyl groups on the surface of the water-soluble chlorinated polypropylene, further increasing the crosslinking density and its hardness and wear resistance;

[0029] (4) The addition of cosolvent can effectively improve the solubility of chlorinated polypropylene, thereby further improving the leveling performance of the coating;

[0030] (5) Octyl acrylate has good flexibility. In this formula, it can improve the flexibility of the coating and help improve the bonding ability between the surface coating and the base coating;

[0031] (6) This process is simple and the emulsification speed is low, which is conducive to industrial application. DETAILED DESCRIPTION

[0032] The specific embodiments of the present invention are further described below in conjunction with the examples. It should be noted that the description of these embodiments is used to help understand the present invention, but does not constitute a limitation of the present invention. In addition, the technical features involved in the various embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0033] In all the following embodiments:

[0034] The hydroxyl-terminated hyperbranched polyesters used were purchased from Wuhan Hyperbranched Resin Technology Co., Ltd., and their specific properties are shown in Table 1 in the content of the invention.

[0035] The chlorinated polypropylenes used were all corresponding chlorinated polypropylene products purchased from Luzhou North Chemical Industry Co., Ltd., and their specific properties are shown in Table 2 in the content of the invention.

[0036] Other raw materials are commercially available products.

[0037] Example 1

[0038] Weigh 10.0 g of acrylic acid, 5.0 g of methacrylic acid, 5.0 g of butyl acrylate, 25.0 g of octyl acrylate and 5.0 g of methyl methacrylate into a beaker to obtain 50 g of an acrylic acid / ester mixture; add a portion of the acrylic acid / ester mixture (about 25 g), 100 g of chlorinated polypropylene K33, 0.5 g of terminal hydroxyl hyperbranched polyester HyPer H101 and 5.0 g of propylene glycol methyl ether into a three-necked flask with a stirrer and a condenser, and gradually heat to about 80° C. until the system becomes a transparent solution. The temperature was lowered to 60°C, and 0.1 g of initiator AIBN and the remaining acrylic acid / ester mixture were gradually added thereto. After the addition was completed, the reaction was stirred at 70°C for 1.0 hour. The temperature was controlled at about 70°C, and triethanolamine was slowly added thereto to neutralize the mixture to a pH value of about 6.8. At 70°C and a stirring rate of 300 rpm, 100 g of a deionized water solution containing 2.0 g of sodium diisooctyl sulfosuccinate emulsifier was gradually added thereto. After the addition was completed, the mixture was emulsified at 70°C and 300 rpm for 1.0 hour, and then 125 g of deionized water was added for dilution to obtain a solvent-free water-soluble chlorinated polypropylene having a solid content of about 40%.

[0039] Example 2

[0040] 25.0 g of acrylic acid, 25.0 g of methacrylic acid, 50.0 g of butyl acrylate, 62.5 g of octyl acrylate and 37.5 g of methyl methacrylate were weighed in a beaker to obtain 200 g of an acrylic acid / ester mixture; a portion of the acrylic acid / ester mixture (about 100 g), 100 g of chlorinated polypropylene CK-800, 3.0 g of terminal hydroxyl hyperbranched polyester HyPer H203 and 2.5 g of propylene glycol butyl ether were added to a three-necked flask with a stirrer and a condenser, and the temperature was gradually raised to about 80° C. until the system became a transparent solution. The temperature was lowered to 70° C., 0.3 g of initiator BPO and the remaining acrylic acid / ester mixture were gradually added thereto. After the addition was completed, the mixture was stirred and reacted at 80° C. for 0.5 hour. The temperature was controlled at about 80° C., and triethylamine was slowly added to neutralize the mixture to a pH value of about 7.0. At this temperature and a stirring rate of 500 rpm, 300 g of a deionized water solution containing 10.0 g of sodium hexadecylsulfonate was gradually added. The mixture was emulsified at 80° C. and 500 rpm for 0.5 hour, and then 300 g of deionized water was added for dilution to obtain a solvent-free water-soluble chlorinated polypropylene having a solid content of about 33%.

[0041] Example 3

[0042] 40.0 g of acrylic acid, 30.0 g of methacrylic acid, 45.0 g of butyl acrylate, 80.0 g of octyl acrylate and 50.0 g of methyl methacrylate were weighed in a beaker to obtain 245 g of an acrylic acid / ester mixture; a portion of the acrylic acid / ester mixture (about 150 g), 100 g of chlorinated polypropylene K11, 2.0 g of terminal hydroxyl hyperbranched polyester HyPer H102 and 3.0 g of diethylene glycol dimethyl ether were added to a three-necked flask with a stirrer and a condenser, and the temperature was gradually raised to about 80° C. until the system became a transparent solution. The temperature was lowered to 75°C, and 0.5 g of initiator TBPO and another part of the acrylic acid / ester mixture were gradually added thereto. After the addition was completed, the mixture was stirred and reacted at 90°C for 2.0 hours; the temperature was lowered to about 85°C, and methyldiethanolamine was slowly added to neutralize to a pH value of about 7.5; at this temperature and a stirring rate of 800 rpm, 300 g of a deionized water solution containing 6.0 g of sodium hexadecylsulfonate emulsifier was gradually added, and emulsification was continued at 85°C and 800 rpm for 2.0 hours, and then 450 g of deionized water was added for dilution to obtain a solvent-free water-soluble chlorinated polypropylene with a solid content of about 32%.

[0043] Example 4

[0044] 50.0 g of acrylic acid, 50.0 g of methacrylic acid, 50.0 g of butyl acrylate, 100.0 g of octyl acrylate and 50.0 g of methyl methacrylate were weighed in a beaker to obtain 300 g of an acrylic acid / ester mixture; a portion of the acrylic acid / ester mixture (about 150 g), 100 g of chlorinated polypropylene CP-30, 1.0 g of terminal hydroxyl hyperbranched polyester HyPer H201 and 2.0 g of ethylene glycol ethyl ether were added to a three-necked flask with a stirrer and a condenser, and the temperature was gradually raised to about 80° C. until the system became a transparent solution. The temperature was lowered to 75°C, and 0.3 g of initiator DCP and another part of the acrylic acid / ester mixture were gradually added thereto. After the addition was completed, the mixture was stirred and reacted at 140°C for 1.5 hours; the temperature was lowered to about 75°C, and N,N-dimethylethanolamine was slowly added to neutralize to a pH value of about 7.0; at this temperature and a stirring rate of 600 rpm, 500 g of a deionized water solution containing 5.0 g of sodium dodecyl polyoxyethylene ether sulfate emulsifier was gradually added, and emulsification was continued at 75°C and 600 rpm for 1.5 hours, and then 240 g of deionized water was added for dilution to obtain a solvent-free water-soluble chlorinated polypropylene with a solid content of about 35%.

[0045] Example 5

[0046] 20.0 g of acrylic acid, 12.0 g of methacrylic acid, 13.0 g of butyl acrylate, 20.0 g of octyl acrylate and 35.0 g of methyl methacrylate were weighed in a beaker to obtain 100 g of an acrylic acid / ester mixture; a portion of the acrylic acid / ester mixture (about 50 g), 100 g of chlorinated polypropylene CP-20, 1.0 g of HyPer H203 and 1.0 g of HyPer H103, 2.0 g of ethylene glycol butyl ether and 1.0 g of propylene glycol butyl ether were added to a three-necked flask with a stirrer and a condenser, and the temperature was gradually raised to about 80° C. until the system became a transparent solution. The temperature was lowered to 75°C, and 0.1g LPO as an initiator, 0.1g 1,1-bis(tert-amylperoxy)cycloalkane and another part of the acrylic acid / ester mixture were gradually added thereto. After the addition was completed, the mixture was stirred and reacted at 90°C for 1.5 hours; the temperature was lowered to about 75°C, and diethanolamine was slowly added to neutralize to a pH value of about 7.0; at this temperature and a stirring rate of 500rpm, 150g of a deionized water solution containing 2.0g sodium dodecyl polyoxyethylene ether sulfate and 1.0g sodium dioctyl sulfosuccinate was gradually added, and emulsification was continued at 75°C and 500rpm for 1.0 hour, and then 140g of deionized water was added for dilution to obtain a solvent-free water-soluble chlorinated polypropylene with a solid content of about 40%.

[0047] Example 6

[0048] 20.0 g of acrylic acid, 17.5 g of methacrylic acid, 17.5 g of butyl acrylate, 40.0 g of octyl acrylate and 25.0 g of methyl methacrylate were weighed in a beaker to obtain 120 g of an acrylic acid / ester mixture; a portion of the acrylic acid / ester mixture (about 70 g), 50 g of chlorinated polypropylene CP-20, 50 g of chlorinated polypropylene CP-30, 1.0 g of HyPer H202 and 0.5 g of HyPerH101, 2.0 g of propylene glycol ethyl ether and 1.5 g of ethylene glycol ethyl ether were added to a three-necked flask with a stirrer and a condenser, and the temperature was gradually raised to about 80° C. until the system became a transparent solution. The temperature was lowered to 75°C, and 0.1g TAPA, 0.1g TAPB, 0.1g 1,1-bis(tert-amylperoxy)-3,3,5-trimethylcyclohexane and another part of the acrylic acid / ester mixture were gradually added thereto. After the addition was completed, the mixture was stirred and reacted at 130°C for 1.5 hours; the temperature was lowered to about 75°C, and diethanolamine was slowly added to neutralize to a pH value of about 7.0; at this temperature and a stirring rate of 400rpm, 300g of a deionized water solution containing 2.0g sodium dodecyl polyoxyethylene ether sulfate and 1.0g sodium dodecylbenzene sulfonate was gradually added, and emulsification was continued at 75°C and 400rpm for 3.0 hours, and then 150g of deionized water was added for dilution to obtain a solvent-free water-soluble chlorinated polypropylene with a solid content of about 32%.

[0049] The particle size of the solvent-free water-soluble chlorinated polypropylene was tested using a Malvern particle size analyzer, and the test of its centrifugal stability grade was based on the literature "Zhang Daohong, Zhou Jiliang, Liu Na. Preparation of water-soluble bisphenol A epoxy resin emulsion, Adhesion, 2008, 2, 30". The volatile organic content (VOC) was determined by gas chromatography. The properties of the products prepared in Examples 1 to 6 are shown in Table 3.

[0050] Table 3 Properties of solvent-free water-soluble chlorinated polypropylene

[0051] Example Particle size, nm Stability, level VOC content, % Example 1 410 6 2.3 Example 2 550 6 2.2 Example 3 480 6 2.7 Example 4 420 6 1.5 Example 5 540 6 1.9 Example 6 510 6 1.3

[0052] The prepared solvent-free water-soluble chlorinated polypropylene has excellent stability and low VOC content, meeting the requirements of green and environmentally friendly coatings.

Claims

1. A method for preparing solvent-free water-soluble chlorinated polypropylene, the specific process of which is as follows: (1) mixing chlorinated polypropylene, a portion of the acrylic acid / ester mixture, a terminal hydroxyl hyperbranched polyester and a cosolvent, heating to 80±5° C., and gradually dissolving the chlorinated polypropylene into a homogeneous solution under stirring; (2) After dissolution, the temperature is lowered to 60-75° C., and the initiator and the remaining acrylic acid / ester mixture are gradually added to the solution of step (1). After the addition is completed, the mixture is stirred and reacted at 70-140° C. for 0.5-2 hours; (3) cooling the mixture to 70-85° C., adding an amine neutralizer to neutralize the mixture to a pH value of 6.8-7.5, and then gradually adding an aqueous solution of an emulsifier, emulsifying the mixture for 0.5-3 hours at a stirring rate of 300-800 rpm, and adding deionized water to dilute the mixture and adjust the solid content, thereby obtaining solvent-free water-soluble chlorinated polypropylene; The acrylic acid / ester mixture is a mixture of acrylic acid, methacrylic acid, butyl acrylate, octyl acrylate and methyl methacrylate; The solid content of the solvent-free water-soluble chlorinated polypropylene is 32-40%; The mass ratio of the chlorinated polypropylene, acrylic acid / ester mixture, terminal hydroxyl hyperbranched polyester and cosolvent is 100:(50-300):(0.5-3.0):(0.5-5.0); the mass ratio of acrylic acid, methacrylic acid, butyl acrylate, octyl acrylate and methyl methacrylate is 1:(0.5-1.0):(0.5-2.0):(0.5-2.5):(0.5-1.75); The hydroxyl-terminated hyperbranched polyester is one or more of HyPer H101, HyPer H102, HyPer H103, HyPer H201, HyPer H202 and HyPer H203 produced by Wuhan Hyperbranched Resin Technology Co., Ltd., and the number average molecular weight of the hydroxyl-terminated hyperbranched polyester is 500-2600 g / mol, and the hydroxyl value is 500-670 mgKOH / g; The chlorinated polypropylene in step (1) is one or more chlorinated polypropylenes having a chlorine content of 23-41%.

2. The preparation method according to claim 1, Features: The cosolvent in step (1) is one or more of propylene glycol methyl ether, propylene glycol ethyl ether, propylene glycol butyl ether, ethylene glycol methyl ether, ethylene glycol ethyl ether, ethylene glycol butyl ether and diethylene glycol dimethyl ether.

3. The preparation method according to claim 1, Features: The initiator is one or more of dibenzoyl peroxide (BPO), azobisisobutyl cyanide (AIBN), tert-butyl peroxide 2-ethylhexanoate (TBPO), lauroyl peroxide (LPO), 1,1-bis(tert-amyl peroxide) cycloalkane, 1,1-bis(tert-amyl peroxy)-3,3,5-trimethylcyclohexane, dicumyl peroxide (DCP), tert-amyl peroxyacetate (TAPA), and tert-amyl peroxybenzoate (TAPB), and the amount used is 0.1% to 0.5% of the mass of the chlorinated polypropylene in step (1).

4. The preparation method according to claim 1, Features: The emulsifier is one or more of diisooctyl sodium sulfosuccinate, sodium dodecyl polyoxyethylene ether sulfate, sodium dodecyl sulfonate, sodium hexadecyl sulfonate and sodium dodecylbenzene sulfonate, and the amount thereof is 2%-10% of the mass of the chlorinated polypropylene in step (1).

5. The preparation method according to claim 1, Features: The amine neutralizing agent is one or more of triethanolamine, diethanolamine, methyldiethanolamine, N,N-dimethylethanolamine, triethylamine, and ammonia water.