A PVDC emulsion for drug packaging

Abstract

The invention discloses a PVDC emulsion for medicine packaging. The raw material formula is as follows by weight: 35-50 parts of vinylidene chloride monomer, 0.5-5 parts of comonomer, 0.1-0.5 parts of initiator, 0.01-0.1 parts of stabilizer, 5-7 parts of dispersant and 30-55 parts of deionized water. The dispersant is silica sol modified by a silane coupling agent. The PVDC emulsion for medicine packaging has the advantages of high thermal stability, low water vapor permeability, long-term storage stability and not easy to be crystallized and embrittled.

Description

Technical Field

[0001] The invention relates to the technical field of polymer materials, in particular to a PVDC emulsion for medicine packaging. Background Art

[0002] Polyvinylidene chloride is referred to as PVDC. It has the characteristics of symmetrical molecular structure, high cohesive energy, compact structure, polymer molecular chain segments are not easy to move, easy to crystallize, etc. It has excellent barrier properties to oxygen and water vapor. PVDC coating film can provide excellent barrier properties. It can be compounded onto polymer substrates such as PVC and PET as an enhanced barrier material. It has many advantages such as oxygen barrier, gas barrier, water barrier, oil resistance, chemical resistance, etc., and provides better water and oxygen barrier protection for food and pharmaceutical packaging. For example, PVDC emulsion is coated on PVC plastic substrate film, which makes the film have better heat sealing, gas barrier, water barrier, fragrance retention and other properties. It is widely used in pharmaceutical packaging. Usually 40g / m 2 , 60g / m 2 and 90g / m 2 The water vapor transmission rate (WVTR) of the coating weight is 0.6g / m 2 ~0.2g / m 2 Therefore, PVDC products are increasingly favored by pharmaceutical and pharmaceutical packaging manufacturers for use in pharmaceutical packaging.

[0003] For example, CN104114585A discloses a blister packaging film with excellent impact resistance, thermal stability and barrier properties, and a vinylidene chloride (VDC) copolymer emulsion suitable for manufacturing the film. The blister packaging film coating and the emulsion contain a vinylidene chloride copolymer with a weight average molecular weight Mw of 120,000 to 300,000, and the vinylidene chloride copolymer is obtained by emulsion copolymerization of 70 to 95 parts by mass of vinylidene chloride and 5 to 30 parts by mass of one or more monomers that can copolymerize with vinylidene chloride (vinylidene chloride and other monomers totaling 100 parts by mass).

[0004] For another example, CN102876149A discloses a self-adhesive polyvinylidene chloride emulsion for coating and its preparation method. The coating is made of raw materials containing the following weight contents: 65-80% of modified PVDC copolymer emulsion, 0.5-5% of adhesion promoter, 3-5% of slip agent, 3-5% of anti-adhesive agent, and 13.5-20% of softened water; the modified PVDC copolymer emulsion is prepared from raw materials containing the following weight contents: 45-60% of vinylidene chloride, 1-3% of acrylic acid, 2-5% of butyl acrylate, 0.5-5% of ethyl methacrylate, 0.5-3% of acrylonitrile, 0.3-0.5% of chain initiator, 0.1-1% of emulsifier, 35.5-37% of softened water, and 0.1-0.5% of defoaming agent.

[0005] For example, CNl08485399A discloses a PVDC aqueous emulsion for coating, which is prepared from the following components by weight: 1 to 5 parts of seed monomer, 45 to 55 parts of VDC monomer, 4 to 10 parts of comonomer, 0.01 to 0.05 parts of initiator, 0.1 to 0.5 parts of seed emulsifier, 0.5 to 3 parts of emulsifier, 0.01 to 0.05 parts of other additives, 0.001 to 0.01 parts of modified additives, and 35 to 40 parts of deionized water.

[0006] The above-mentioned prior arts all use traditional anionic or nonionic surfactants to synthesize PVDC polymers that can be used in drug packages. However, there are some disadvantages: they are easily decomposed by heat to produce small molecular migrants (manifested as emulsifier precipitation), and the heat resistance temperature of the material is not high (manifested as poor thermal weight loss data); or the coating contains small molecular hydrophilic substances such as emulsifiers, and the water vapor transmission rate performance is general (under the same test conditions, between 0.5-0.7); or it is easy to crystallize and become brittle after long-term storage. Summary of the invention

[0007] In order to overcome the defects of the prior art, the present invention provides a PVDC emulsion for pharmaceutical packaging which has high thermal stability, low water vapor permeability, long-term storage stability and is not prone to crystallization and embrittlement.

[0008] In order to solve the above technical problems, the technical solution adopted by the present invention is: a PVDC emulsion for pharmaceutical packaging, wherein the raw material formula is as follows by weight: 35-50 parts of vinylidene chloride monomer, 0.5-5 parts of copolymer monomer, 0.1-0.5 parts of initiator, 0.01-0.1 parts of stabilizer, 5-7 parts of dispersant, and 30-55 parts of deionized water, wherein the dispersant is a silica sol modified by a silane coupling agent.

[0009] As a preferred embodiment of the present invention, the silica sol modified by the silane coupling agent has the following structure:

[0010]

[0011] Wherein, R' is vinyl, phenyl, amino or mercapto.

[0012] As a preferred embodiment of the present invention, the silica sol modified by the silane coupling agent is one of CC301, CC401 and CC503.

[0013] As a preferred embodiment of the present invention, the initiator is one of ammonium persulfate, potassium persulfate and sodium persulfate.

[0014] As a preferred embodiment of the present invention, the stabilizer is one of polyvinyl pyrrolidone, polyvinyl alcohol and polyhydroxypropyl methylcellulose.

[0015] As a preferred embodiment of the present invention, the comonomer is methyl acrylate or n-butyl acrylate.

[0016] The present invention optimizes the polymerization formula, adopts silica sol modified by silane coupling agent as the main dispersant, replaces the traditional anionic or nonionic surfactant, and synthesizes an organic-inorganic hybrid PVDC emulsion for drug packaging. The PVDC emulsion for drug packaging of the present invention is particularly suitable for the preparation of PVC / PVDC composite hard sheets for drug blister packaging, can maintain high impact resistance for a long time after coating, does not generate cracks during processing, and has improved thermal stability and water vapor barrier properties.

[0017] The structure schematic diagram of the silica latex particles in the silica sol modified by the silane coupling agent in the present invention is shown in the following figure:

[0018]

[0019] Where R represents CH3, C2H5.

[0020] Its mechanism of action is to modify the silica particles in the silica sol by silane coupling agent, forming organic silicon functional groups on the surface of inorganic silica, thereby effectively improving the surface polarity, and adjusting the interfacial tension between the nanoparticles and the reaction monomers by adding the silane coupling agent to achieve a hydrophilic-lipophilic balance and maintain the dispersion stability of the emulsification and reaction process. Its reaction mechanism can be described as the following three processes:

[0021] (1) Organosilane hydrolysis

[0022] R'Si(OR)3+3H2O→R'Si(OH)3+3ROH

[0023] (2) Organosilane self-condensation

[0024]

[0025] (3) Reaction of organosilane with the surface silanol groups of SiO2 particles in silica sol

[0026]

[0027] Wherein, R' can be an organic functional group such as vinyl, phenyl, amino, thiol, etc.

[0028] The silica sol modified by the silane coupling agent used in the present invention has good hydrophilicity and lipophilicity, and is adsorbed on the surface of the VDC emulsion droplets to make the VDC emulsion droplets uniformly and stably dispersed. Polymerization occurs inside the VDC emulsion droplets, and the persulfate initiator reacts with the VDC monomer in the aqueous phase. During the polymerization process, the PVDC protective colloid and the surface-modified colloidal silica undergo a grafting reaction to form a stable nano-silicon dioxide hybrid PVDC copolymer emulsion. The colloidal silica acts as a three-dimensional crosslinking agent during the polymerization reaction, which can improve the performance of the resulting PVDC dispersion. This special organic-inorganic composite material can make the coating film more compact, thereby achieving the purpose of improving the thermal stability of the polymer, reducing the water vapor permeability of the composite coating, and preventing the brittleness of the long-term storage, so that the medicine is better protected. The PVC / PVDC composite hard sheet prepared by coating the PVDC emulsion on the PVC sheet has significantly improved heat resistance, better thermal stability under conventional processing conditions, and water vapor permeability performance is much higher than the industry standard, and has better toughness and small long-term brittleness changes.

[0029] Compared with the prior art, the present invention has the following beneficial effects:

[0030] 1. The silica latex particles in the silica sol modified by the silane coupling agent in the present invention have good hydrophilicity and lipophilicity, and are adsorbed on the latex particles to form a stable nano-silicon dioxide hybrid PVDC copolymer emulsion. This special organic-inorganic composite material can improve the thermal stability of the polymer. The PVDC emulsion for pharmaceutical packaging of the present invention has a stable storage time of more than 12 days at 60°C; the time required for weight loss of ≥0.3% at 160°C is more than 40s; the residual mass after heating at 160°C for 2h is more than 97.16%;

[0031] 2. The PVC / PVDC composite hard sheet prepared by coating the PVDC emulsion for pharmaceutical packaging of the present invention on PVC sheet has significantly improved impact resistance and heat resistance, better thermal stability under conventional processing conditions, water vapor permeability performance far higher than the industry standard, better toughness, small long-term brittleness change and other performance characteristics. The impact resistance after coating for one year is 288KJ / m 2 After one week, the water vapor transmission rate is 0.43g / m 2 ·Day or less, oxygen permeability is 0.76cm 3 / m 2 ·Day or less. DETAILED DESCRIPTION

[0032] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with embodiments. It should be understood that the following description is only used to explain the present invention but not to limit the present invention.

[0033] The equipment and raw materials described in the embodiments of the present invention can be obtained commercially, among which:

[0034] The manufacturer of silica sol CC503, CC401 and CC301 is Nouryon.

[0035] Example 1

[0036] A PVDC emulsion for drug packaging, the raw material formula of which is as follows:

[0037]

[0038] The preparation method comprises the following steps:

[0039] (1) Preparation of initiator aqueous solution: weigh 180 g of ammonium persulfate (APS), add deionized water to make a 10 kg ammonium persulfate aqueous solution, and set aside;

[0040] (2) Preparing a pre-emulsion: In a 100 L preparation kettle, add 10 g of polyvinyl pyrrolidone and the remaining deionized water, stir at 60 rpm for 20 min, then add 5.2 kg of silica sol CC503, and then add 1 mol / L CH3COOH aqueous solution to adjust the pH to 3, then add 40 kg of vinylidene chloride and 3.5 kg of methyl acrylate, stir at 130 rpm for 30 min, and obtain a pre-emulsion for standby use;

[0041] (3) PVDC emulsion polymerization: After the sealing test of the 100L polymerization kettle is passed, the pressure is evacuated to -0.09Mpa, and nitrogen is introduced to the pressure to 0.3Mpa. The polymerization kettle is heated to 70°C at a speed of 85rpm, and the pre-emulsion obtained in step (2) is added at one time, and then the ammonium persulfate aqueous solution obtained in step (1) is continuously added at a rate of 24g / min to start the reaction. After reacting for 300min, the remaining ammonium persulfate aqueous solution is added at one time, and the reaction is continued for 3.5h. The reaction is terminated, the reactor is cooled to 20°C, and the pH is adjusted to 1.9 with ammonia water to obtain a PVDC emulsion for pharmaceutical packaging. The performance parameters of the emulsion are shown in Table 1.

[0042] Example 2

[0043] A PVDC emulsion for drug packaging, the raw material formula of which is as follows:

[0044]

[0045] The preparation method is the same as that of Example 1. The performance parameters of the emulsion are shown in Table 1.

[0046] Example 3

[0047] A PVDC emulsion for drug packaging, the raw material formula of which is as follows:

[0048]

[0049]

[0050] The preparation method is the same as that of Example 1. The performance parameters of the emulsion are shown in Table 1.

[0051] Example 4

[0052] A PVDC emulsion for drug packaging, the raw material formula of which is as follows:

[0053]

[0054] The preparation method is the same as that of Example 1. The performance parameters of the emulsion are shown in Table 1.

[0055] Example 5

[0056] A PVDC emulsion for drug packaging, the raw material formula of which is as follows:

[0057]

[0058] The preparation method is the same as that of Example 1. The performance parameters of the emulsion are shown in Table 1.

[0059] Example 6

[0060] A PVDC emulsion for drug packaging, the raw material formula of which is as follows:

[0061]

[0062]

[0063] The preparation method is the same as that of Example 1. The performance parameters of the emulsion are shown in Table 1.

[0064] Example 7

[0065] A PVDC emulsion for drug packaging, the raw material formula of which is as follows:

[0066]

[0067] The preparation method is the same as that of Example 1. The performance parameters of the emulsion are shown in Table 1.

[0068] Comparative Example

[0069] The product was prepared according to the method of Example 2 of Chinese Patent Publication No. CN104114585A. The performance parameters of the emulsion are shown in Table 1.

[0070] Performance Test:

[0071] 1. Storage stability test

[0072] The PVDC emulsion products prepared in Examples 1 to 7 and the comparative example were placed in a 60°C oven for constant temperature and the changes in the appearance of the emulsions were observed. The results are shown in Table 1. As can be seen from Table 1, the PVDC emulsions prepared in Examples 1 to 7 can be stored for a long time and have better storage stability.

[0073] 2. Heat resistance test

[0074] The PVDC film was prepared using a heated wire rod coating tester at 120 mm / s, 20 μm, and 120°C. At 160°C, in an air atmosphere, a thermogravimetric analyzer (NETZSCH TG 209) was used to test the weight change at 160°C for 2 hours and the time required for weight loss ≥ 0.3%. The PVDC films prepared in Examples 1 to 7 and the comparative example were tested, and the results are shown in Table 1. As can be seen from Table 1, the PVDC films prepared using the PVDC emulsion products of Examples 1 to 7 show low degradation, and it can be seen that the addition of an appropriate amount of silica sol improves the heat resistance of the PVDC emulsion after film formation to a certain extent.

[0075] 3. Impact resistance and barrier properties test

[0076] The surface of the PVC hard sheet (thickness is about 250um) is treated with corona discharge and a layer of 2g / m 2 The adhesive (the adhesive is a solution of polyurethane dissolved in ethyl acetate) was applied, hot air dried for 20 seconds, and then the PVDC emulsion prepared above was coated on the surface. The coating thickness was controlled to be 25±3um. After infrared drying, the film was placed in a drying room at 50°C for 48 hours to obtain a PVDC / PVC composite hard sheet. The impact resistance and barrier properties of the composite hard sheet were tested. The test results are shown in Tables 2 and 3, respectively. Among them:

[0077] Impact resistance is in accordance with the standard YBB00222005-2015;

[0078] The water vapor transmission rate test method was carried out according to YBB00222005-2015, and the water vapor transmission rate was measured using PERME W3 / 031 (manufactured by Jinan Labthink) at 38°C and 100% relative humidity;

[0079] The oxygen permeability test method was carried out according to YBB00222005-2015, and the water vapor permeability was measured using PERME OX2 / 231 (manufactured by Jinan Labthink) at 23°C and a relative humidity of 100%.

[0080] Table 1 Performance of PvDC emulsion products obtained in Examples and Comparative Examples

[0081]

[0082] Table 2 Impact resistance test results of PvDC / PvC composite hard sheet (PvDC emulsion placed at room temperature for 2 weeks)

[0083]

[0084] Table 3 Barrier performance test results of PvC / PvDC composite hard sheet

[0085]

Claims

1. A PVDC emulsion for pharmaceutical packaging, the raw material formula of which is as follows: Deionized water 45kg Initiator: Sodium persulfate 280g Stabilizer: polyvinyl alcohol 20g Dispersant: Silica sol CC401 5.9kg Vinylidene chloride monomer 46kg Comonomer: n-butyl acrylate 1.5kg It is characterized in that The PVDC emulsion for drug packaging is prepared by the following method: (1) Prepare the initiator aqueous solution: weigh 280 g of sodium persulfate and add deionized water to make a 10 kg sodium persulfate aqueous solution for later use; (2) Preparation of pre-emulsion: In a 100L preparation kettle, add 20g of polyvinyl alcohol and the remaining deionized water, stir at 60rpm for 20min, then add 5.9kg of silica sol CC401, and then add 1mol / L CH3COOH aqueous solution to adjust the pH to 3, then add 46kg of vinylidene chloride and 1.5kg of n-butyl acrylate, stir at 130rpm for 30min to obtain a pre-emulsion for later use; (3) After the sealing test of the polymerization kettle is passed, the pressure is evacuated to -0.09 MPa, and nitrogen is introduced to the pressure to 0.3 MPa. The polymerization kettle is heated to 70°C at a speed of 85 rpm, and the pre-emulsion obtained in step (2) is added at one time. Then, the initiator aqueous solution obtained in step (1) is continuously added at a rate of 24 g / min to start the reaction. After reacting for 300 min, the remaining initiator aqueous solution is added at one time, and the reaction is continued for 3.5 h. The reaction is terminated, the reactor is cooled to 20°C, and the pH is adjusted to 1.9 with aqueous ammonia to obtain a PVDC emulsion for pharmaceutical packaging.

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