Chlorosulfonated propylene-based polymer

Abstract

To provide a polymer material having excellent adhesion between polypropylene-based resin and metal, in particular, exhibiting excellent adhesion even to a metal substrate without surface modification.SOLUTION: A chlorosulfonated propylene-based polymer comprising a propylene-based polymer having chlorine and chlorosulfonyl groups bonded thereto, wherein the propylene-based polymer is block polypropylene, and the chlorine content is 23.1-40.0 wt.%.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a chlorosulfonated propylene polymer in which chlorine and chlorosulfone groups are bonded to a propylene polymer. [Background technology]

[0002] Traditionally, welding, rivets, bolts, and other methods have been used to join metals, but with the advancement of science and technology today, the performance and functionality of materials required has become more stringent, and there is a growing demand for adhesion between dissimilar materials. In order to meet these demands, attention is being paid to and advances are being made in adhesive technology.

[0003] Furthermore, technological innovations in the automotive and other fields are expected to make bonding technology for dissimilar materials such as polypropylene and metals increasingly important.

[0004] Polypropylene is widely used in a wide range of applications due to its excellent processability, physical properties, recyclability, and price. However, it is a poorly adhesive material, and it is difficult to ensure sufficient adhesive strength even with surface treatments (see, for example, Non-Patent Document 1).

[0005] Regarding the improvement of adhesion to polypropylene-based resins, chlorosulfonated polypropylenes made from propylene homopolymers or propylene-ethylene copolymers have been studied (see, for example, Patent Document 1). However, this study involved preparing an aqueous emulsion as a primer for polypropylene-based resins and evaluating the adhesion of the coating film, and no study was conducted on the adhesion of dissimilar materials, such as polypropylene-based resins and metals. [Prior art documents] [Non-patent literature]

[0006] [Non-Patent Document 1] Journal of the Adhesion Society of Japan Vol.54 No6(2018) Section 212~ [Patent documents]

[0007] [Patent Document 1] Japanese Patent Application Laid-Open No. 2008-127436 Summary of the Invention [Problem to be solved by the invention]

[0008] The present invention has been made in view of the above problems, and an object of the present invention is to provide a chlorosulfonated propylene polymer that can exhibit excellent adhesion to dissimilar materials, i.e., resins such as polypropylene and metals. [Means for solving the problem]

[0009] The present inventors have conducted extensive research to solve the above problems and have completed the present invention, which relates to the following items [1] to [6].

[0010] [1] A chlorosulfonated propylene polymer in which chlorine and chlorosulfone groups are bonded to a propylene polymer, the propylene polymer being a block polypropylene and having a chlorine content of 23.1 to 40.0 wt%.

[0011] [2] The chlorosulfonated propylene polymer according to [1], which has a sulfur content of 0.1 to 5.0% by weight.

[0012] [3] The chlorosulfonated propylene polymer according to [1], which has a weight-average molecular weight of 100,000 to 800,000.

[0013] [4] The chlorosulfonated propylene polymer according to [1], wherein the ethylene content of the block polypropylene is 2.0 to 25.0 mol %.

[0014] [5] An adhesive comprising the chlorosulfonated propylene polymer according to [1].

[0015] [6] A pressure-sensitive adhesive comprising the chlorosulfonated propylene polymer according to [1]. [Effects of the Invention]

[0016] The chlorosulfonated propylene polymer of the present invention makes it possible to produce an adhesive that exhibits excellent adhesion to dissimilar materials, such as resins such as polypropylene and metals. DETAILED DESCRIPTION OF THE INVENTION

[0017] The present invention will be described in detail below.

[0018] The chlorosulfonated propylene polymer according to one embodiment of the present invention is a chlorosulfonated propylene polymer in which chlorine and chlorosulfone groups are bonded to a propylene polymer, the propylene polymer being a block polypropylene and having a chlorine content of 23.1 to 40.0 wt %.

[0019] The chlorine content of the chlorosulfonated propylene polymer is 23.1% by weight or more, preferably 23.5% by weight or more, and more preferably 24.0% by weight or more, in order to obtain excellent adhesion, particularly to metals. Also, in order to obtain excellent adhesion, particularly to low-polarity resins such as polypropylene and to metals, the chlorine content is 40.0% by weight or less, preferably 35.0% by weight or less, more preferably 30.0% by weight or less, and even more preferably 27.0% by weight or less.

[0020] The sulfur content of the chlorosulfonated propylene polymer is preferably 0.1% by weight or more, more preferably 0.2% by weight or more, and even more preferably 0.3% by weight or more, because excellent adhesion, particularly to metals, is obtained. The sulfur content is preferably 5.0% by weight or less, more preferably 4.0% by weight or less, and even more preferably 3.0% by weight or less, because the stability of the polymer is excellent.

[0021] The weight-average molecular weight of the chlorosulfonated propylene polymer is preferably 100,000 or more, more preferably 150,000 or more, and even more preferably 200,000 or more, since excellent adhesive properties can be obtained. Also, the weight-average molecular weight is preferably 800,000 or less, more preferably 700,000 or less, and even more preferably 600,000 or less, since excellent processability can be obtained.

[0022] The chlorosulfonated propylene polymer may be obtained by any method, and can be obtained, for example, by chlorosulfonating a raw material propylene polymer that constitutes the chlorosulfonated propylene polymer.

[0023] The propylene polymer that constitutes the main chain skeleton of the chlorosulfonated propylene polymer is block polypropylene. Here, block polypropylene is a polymer in which a polyethylene component and / or an ethylene-propylene copolymer component is dispersed in a polypropylene homopolymer. Block polypropylene is also called impact polypropylene, impact copolymer, ICP, etc., and this term encompasses all of these. Block polypropylene can be produced, for example, by two-stage polymerization in which propylene homopolymerization and copolymerization of propylene and ethylene are carried out consecutively.

[0024] The ethylene content of the block polypropylene is preferably 2.0 mol% or more, more preferably 3.0 mol% or more, and even more preferably 4.0 mol% or more, because excellent adhesive properties are obtained, particularly excellent adhesive properties to low-polarity resins such as polypropylene and metals, and is preferably 25.0 mol% or less, more preferably 23.0 mol% or less, even more preferably 21 mol% or less, and particularly preferably 20.0 mol% or less, because excellent heat resistance is obtained.

[0025] The method for obtaining a chlorosulfonated propylene polymer is not particularly limited, and examples thereof include a solution method in which a propylene polymer is uniformly dissolved in an inert solvent and reacted, a suspension method in which a propylene polymer is suspended in a solvent and reacted, a dissolution method in which a propylene polymer is dissolved in the absence of a solvent and reacted, etc. Among these, the solution method, which allows uniform chlorination and chlorosulfonation of a propylene polymer, is preferred.

[0026] The solvent used for chlorosulfonation by the solution method is not particularly limited, and examples thereof include carbon tetrachloride, trichloroethane, tetrachloroethane, chloroform, chlorobenzene, and the like, from the viewpoints of solubility and reactivity, with trichloroethane being particularly preferred due to its favorable reactivity.

[0027] The chlorosulfonating agent used in chlorosulfonating a propylene polymer is not particularly limited, and sulfur dioxide, chlorine, sulfuryl chloride, and the like may be used alone or in combination. Furthermore, a catalyst for promoting the chlorosulfonation reaction may be used as needed. Examples of the catalyst include azo compounds and organic peroxides. Examples of azo compounds include α,α'-azobisisobutyronitrile, azobiscyclohexanecarbonitrile, and 2,2'-azobis(2,4-dimethylvaleronitrile). Examples of organic peroxides include benzoyl peroxide, acetyl peroxide, t-butyl peroxide, and t-butyl perbenzoate. Azo compounds are preferred because of their high handling stability, and α,α'-azobisisobutyronitrile is particularly preferred because it allows for appropriate chlorination and chlorosulfonation reactions. Furthermore, amino compounds such as pyridine and quinoline, or phosphate ester compounds may be added as co-catalysts to promote the chlorosulfonation reaction, as needed.

[0028] The chlorinating agent used in chlorinating the propylene polymer is not particularly limited, and chlorinating agents such as chlorine gas, thionyl chloride, and sulfuryl chloride may be used alone or in combination. Furthermore, a catalyst or the like that promotes the chlorination reaction may be used as needed. Examples of the catalyst include azo compounds and organic peroxides. Examples of azo compounds include α,α'-azobisisobutyronitrile, azobiscyclohexanecarbonitrile, and 2,2'-azobis(2,4-dimethylvaleronitrile). Examples of organic peroxides include benzoyl peroxide, acetyl peroxide, t-butyl peroxide, and t-butyl perbenzoate. Azo compounds are preferred because of their high stability in handling, and α,α'-azobisisobutyronitrile is particularly preferred because it allows for appropriate chlorination and chlorosulfonation reactions. Furthermore, amino compounds such as pyridine and quinoline, or phosphate ester compounds may be added as co-catalysts to promote the chlorination reaction, as needed.

[0029] The reaction temperature during chlorosulfonation or chlorination is not particularly limited and can be appropriately selected depending on the melting point of the raw material polymer, and in particular, taking into consideration reactivity and handleability, it is preferably 50 to 150° C., more preferably 60 to 130° C. Furthermore, the reaction pressure during chlorosulfonation or chlorination is not particularly limited and is, for example, 0 to 1.0 MPa, and preferably 0 to 0.6 MPa to ensure that the chlorosulfonation and chlorination reactions proceed appropriately.

[0030] After the chlorosulfonation or chlorination reaction is completed, sulfur dioxide gas or hydrogen chloride remaining in the reaction solution can be removed by introducing nitrogen. There is no problem in removing sulfur dioxide gas or hydrogen chloride under reduced pressure.

[0031] Furthermore, additives such as antioxidants and stabilizers may be added either before or after the chlorosulfonation or chlorination reaction. The type of additive is not particularly limited, and examples include hindered phenol-based antioxidants such as 4-t-butylcatechol, 2,6-di-t-butyl-p-cresol, and triethylene glycol bis[3-(3-t-butyl-4-hydroxy-5-methylphenyl)propionate], and epoxy compounds such as epoxidized polybutadiene and bisphenol A resin. These may be used alone or in combination of two or more. The timing of adding the additive is not particularly limited, but considering the ease of operation and the efficiency of the additive, it is preferable to add the additive after the chlorosulfonation or chlorination reaction and after removing the residual gas.

[0032] The method for separating the polymer and the solvent from the chlorosulfonated or chlorinated product polymer solution is not particularly limited, but for example, steam distillation, a drum dryer, a vented extruder, etc. can be used.

[0033] The chlorosulfonated propylene polymer can be used as an adhesive by adding a crosslinking agent, a crosslinking aid, an acid acceptor, a plasticizer, a solvent, a viscosity modifier, a flexibility imparting agent, an inorganic filler, an antioxidant, an antiaging agent, an adhesion promoter, a silane coupling agent, etc. The amounts of these additives to be added may be conventional amounts as long as they do not contradict the object of the present invention.

[0034] The chlorosulfonated propylene polymer can be used as an adhesive that exhibits excellent adhesion to various substrates, particularly excellent adhesion between resins such as polypropylene and metals. For metals, such as iron, stainless steel, steel, carbon steel, and aluminum, as well as alloys thereof, metal oxides, and metal hydroxides, and substrates having these at least on their surfaces, the adhesive exhibits excellent adhesion regardless of the presence or absence of surface treatment or surface modification such as primer treatment. Similarly, by forming a composition with an adhesive component, an adhesive that exhibits excellent adhesion between resins such as polypropylene and metals can be obtained. The adhesive component is not particularly limited, but examples thereof include natural rubber-based adhesives, polyisobutylene-based adhesives, styrene-butadiene rubber-based adhesives, styrene-isoprene-styrene block copolymer-based adhesives, acrylic-based adhesives, silicone-based adhesives, and urethane-based adhesives. [Example]

[0035] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples.

[0036] In the examples, the ethylene content of the propylene polymer, and the chlorine content, sulfur content, melting point, heat of fusion, molecular weight, and adhesive strength of the chlorosulfonated propylene polymer were measured as follows:

[0037] [Measurement of ethylene content in propylene polymers] The ethylene content of propylene polymers is 13 Measurement was performed by C-NMR.

[0038] The solvent was 1,1,2,2-tetrachloroethane-d2 at 130°C using a Bruker AVANCE NEO700. 13 C-NMR measurement was carried out, and from the obtained spectrum, each peak was assigned according to the following references 2 and 3. The ethylene content was calculated from the integral value of each assigned peak.

[0039] Reference 2: JCRandall, J.Macromol.Sci., Rev.Macromol.Chem.Phys., 1989, C29, p.201-317 Reference 3: GJ Ray et al., Macromolecules, 1977, 10, p.773-778 [Measurement of chlorine content and sulfur content] The chlorine content of the chlorosulfonated propylene polymer was determined by burning the sample using a combustion flask method, absorbing the resulting hydrochloric acid in pure water, and then quantifying it with an automatic titrator using a 0.05 mol / L silver nitrate solution. The sulfur content was measured using the oxygen combustion flask method in accordance with JIS K6233 (1998 edition).

[0040] <Molecular weight measurement> The molecular weight of the polymer solution obtained by dissolving 10 mg of chlorosulfonated propylene polymer in 10 mL of THF was measured by GPC. The number average molecular weight (Mn) and weight average molecular weight (Mw) were calculated in terms of polystyrene using standard polystyrene (manufactured by Tosoh Corporation). The measurement conditions are shown below.

[0041] Model: (Product name) HLC (registered trademark) 8420GPC Solvent: THF Column temperature: 40℃ ·Measurement concentration: 10mg / 10mL ·Injection volume: 200μL Column: TSKgel® G7000HXL (manufactured by Tosoh Corporation) → TSKgel® GMHXL (manufactured by Tosoh Corporation) x 2 The chlorosulfonated propylene polymers of Examples 1 to 3 and Comparative Examples 1 to 4 were synthesized by the following methods, using the following raw materials.

[0042] [Raw materials] The following commercially available products were used as raw materials for the synthesis of the chlorosulfonated propylene polymers.

[0043] PP1: Block polypropylene (manufactured by Japan Polypropylene Corporation, product name: Novatec (registered trademark) BC03B, ethylene content: 14 mol%, melt mass-flow rate (JIS K 7210): 30 g / 10 min) PP2: Propylene homopolymer (manufactured by Japan Polypropylene Corporation, trade name: Novatec (registered trademark) SA03, ethylene content: 0 mol%, melt mass-flow rate (JIS K 7210): 30 g / 10 min) PP3: Random polypropylene (manufactured by Japan Polypropylene Corporation, product name: Novatec (registered trademark) MG03BD, ethylene content: 3 mol%, melt mass-flow rate (JIS K 7210): 30 g / 10 min) Sulfuryl chloride (Fujifilm Wako Pure Chemical Industries, Ltd.) α,α'-Azobisisobutyronitrile (Fujifilm Wako Pure Chemical Industries, Ltd.) Pyridine (Fujifilm Wako Pure Chemical Industries, Ltd.) 1,1,2-Trichloroethane (Tokyo Chemical Industry Co., Ltd.) [Synthesis of chlorosulfonated propylene polymer] Under a nitrogen atmosphere, a propylene-based polymer and 1,1,2-trichloroethane were added to a glass pressure reactor according to Table 1 and dissolved at 130°C. After dissolution was complete, the reaction solution was cooled to 120°C. Pyridine was added to this polymer solution according to Table 1. At 120°C, a 1,1,2-trichloroethane solution of α,α'-azobisisobutyronitrile adjusted to 2 g / L was added dropwise at a rate of 0.1 mL / min, while sulfuryl chloride was added at a rate of 0.8 mL / min, and the pressure was adjusted to 0.25 MPaG. After adding sulfuryl chloride for the specified time according to Table 1, the temperature and pressure were lowered, and nitrogen gas was introduced at a rate of 150 mL / min at 100°C and atmospheric pressure for 1 hour. The solvent was distilled off from the resulting reaction solution using a double drum dryer, yielding a chlorosulfonated propylene-based polymer.

[0044] Examples 1 to 3 and Comparative Examples 1 to 3 were evaluated by the following adhesion / peel test evaluation method.

[0045] [Evaluation method for adhesive peel test] The evaluation polymer was placed in a 0.5 mm thick mold and preheated to 140°C for 3 minutes at 50 kgf / cm 2 , then 100kgf / cm 2 , 50kgf / cm at 23℃ after 5 minutes of heat pressing 2 The sheet was then cooled and pressed for 3 minutes to obtain a 0.5 mm sheet for adhesion testing. The obtained sheet was used to prepare a test piece for adhesion peel testing, and the peel strength was measured. The test piece was prepared by sandwiching the adhesion test sheet between two adherends and heating at 160°C and 50 kgf / cm 2 , after 5 minutes of heat pressing, 50 kgf / cm at 23°C 2 The specimen was prepared by pressing for 3 minutes under cooling pressure. The adherends used were pure aluminum (A1050P) (thickness: 0.3 mm) and polypropylene (thickness: 0.3 mm).

[0046] Adhesion to aluminum was evaluated as excellent if it was 8 N / cm or more, and poor if it was less than that. Adhesion to polypropylene was evaluated as excellent if it was 10 N / cm or more, and poor if it was less than that.

[0047] As can be seen from Table 1, Examples 1 to 3 were evaluated as excellent for both aluminum and polypropylene, resulting in excellent adhesion to both polypropylene and metal. Comparative Examples 2 and 3 had excellent adhesion to polypropylene but poor adhesion to metal. Comparative Example 1 had poor adhesion to both metal and polypropylene.

[0048] [Table 1] [Industrial Applicability]

[0049] The present invention exhibits good adhesive properties for bonding dissimilar materials, particularly polypropylene to metal, and therefore can be mixed with various adhesives to provide an adhesive composition for dissimilar materials.

Claims

1. A chlorosulfonated propylene polymer in which chlorine and chlorosulfone groups are bonded to a propylene polymer, the propylene polymer being a block polypropylene and having a chlorine content of 23.1 to 40.0 wt %.

2. 2. The chlorosulfonated propylene polymer according to claim 1, wherein the sulfur content is 0.1 to 5.0% by weight.

3. The chlorosulfonated propylene polymer according to claim 1, having a weight average molecular weight of 100,000 to 800,000.

4. 2. The chlorosulfonated propylene polymer according to claim 1, wherein the ethylene content of the block polypropylene is 2.0 to 25.0 mol %.

5. An adhesive comprising the chlorosulfonated propylene polymer according to claim 1.

6. A pressure-sensitive adhesive comprising the chlorosulfonated propylene polymer according to claim 1.

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