A full plastic type composite toothpaste tube sheet suitable for recycling and a preparation process thereof

Abstract

The present application relates to toothpaste tube sheet material technical field, and disclose a kind of suitable for recycling full plastic composite toothpaste tube sheet material and its preparation process, comprising: synthetic monomer quaternary ammonium salt intercalation agent and double quaternary ammonium salt intercalation agent;Based on covalent bond effect, hydrogen bond effect and electrostatic interaction, using monomer quaternary ammonium salt intercalation agent and double quaternary ammonium salt intercalation agent jointly intercalation modification treatment to graphene oxide, intercalation modification type graphene oxide is prepared;Intercalation modification type graphene oxide is dispersed in ethylene-vinyl alcohol copolymer matrix, and organic-inorganic composite modifier is prepared;Organic-inorganic composite modifier is added to single PP material nine-layer co-extrusion film, nine-layer co-extrusion blow molding film process is used, and full plastic composite toothpaste tube sheet material with thickness of 250~300 μm is prepared, which has very excellent mechanical properties and barrier properties, and is suitable for recycling, and can be used to manufacture toothpaste tube packaging material.

Description

Technical Field

[0001] This invention relates to the field of toothpaste tube sheet technology, specifically to a recyclable all-plastic composite toothpaste tube sheet and its preparation process. Background Technology

[0002] Currently, the composite packaging sheets used in toothpaste are mainly aluminum-plastic composite sheets and all-plastic composite sheets. The initial thickness of all-plastic composite sheets was generally around 350μm, with the barrier layer EVOH reaching a thickness of 25μm. With advancements in manufacturing technology, the material thickness has gradually decreased from 350μm, and now commonly used thicknesses are 300μm and 275μm, while the EVOH thickness has been reduced to 15μm. This reduction in overall sheet thickness lowers the material's mechanical properties, potentially impacting its normal use. Furthermore, thinning the barrier material also reduces its barrier performance.

[0003] How to ensure the performance of sheet materials while reducing their thickness? Thanks to the continuous development of materials science, the development and application of various new barrier materials have effectively solved a series of problems.

[0004] Graphene is a two-dimensional material with an ultrathin, perfectly structured sheet-like structure. Its excellent barrier properties have attracted considerable attention; studies have shown that even the smallest he atom cannot pass through a single layer of graphene. However, the demanding preparation conditions and complex processes of graphene production limit its large-scale production and application. Graphene oxide, a derivative of graphene, possesses a similar two-dimensional sheet-like structure. Although its surface contains numerous defects caused by oxygen-containing functional groups, it still exhibits excellent barrier properties for small molecules. Furthermore, graphene oxide can be mass-produced from graphite through chemical oxidation, making it a promising candidate for improving the barrier properties of polymers. Summary of the Invention

[0005] This invention independently developed a novel organic-inorganic composite modifier, which simultaneously improves the mechanical and barrier properties of single PP material, thus preparing an all-plastic composite sheet. This all-plastic composite sheet is very suitable for recycling and can be used to manufacture toothpaste tube packaging materials.

[0006] A process for preparing a recyclable all-plastic composite toothpaste tube sheet includes the following steps:

[0007] Step 1: Synthesize mono-quaternary ammonium salt intercalating agents and bis-quaternary ammonium salt intercalating agents;

[0008] The chemical structural formula of the monoquaternary ammonium salt intercalating agent is:

[0009]

[0010] The chemical structural formula of the bisquaternary ammonium salt intercalating agent is:

[0011]

[0012] Step 2: Based on covalent bonding, hydrogen bonding, and electrostatic interactions, graphene oxide is intercalated and modified using both mono-quaternary ammonium salt intercalating agents and bis-quaternary ammonium salt intercalating agents to obtain intercalated modified graphene oxide; the intercalated modified graphene oxide is then composited with ethylene-vinyl alcohol copolymer to prepare an organic-inorganic composite modifier.

[0013] Step 3: Add an organic-inorganic composite modifier to a single polypropylene raw material and use a nine-layer co-extrusion blow molding process to prepare a fully plastic composite toothpaste tube sheet suitable for recycling.

[0014] Preferably, the preparation method of the monoquaternary ammonium salt intercalating agent is as follows:

[0015] Step S2-1: A protic acid catalyst catalyzes the Mannich condensation reaction of paeonol containing α-H with formaldehyde and dimethylamine to prepare a tertiary amine monomer.

[0016] Step S2-2: Based on the nucleophilic substitution mechanism, a monoquaternary ammonium salt intercalating agent is prepared by quaternization reaction between the tertiary amine functional group of the tertiary amine monomer and the chlorine functional group of 3-chloropropyltrimethoxysilane.

[0017] Preferably, the protic acid catalyst is one of sulfuric acid, hydrochloric acid, and phosphoric acid.

[0018] Preferably, the preparation method of the bisquaternary ammonium salt intercalating agent is as follows: based on the nucleophilic substitution mechanism, the tertiary amine functional group of the tertiary amine monomer undergoes a quaternization reaction with the chlorine functional group of 1,5-dichloropentane, and the molar ratio of the tertiary amine monomer to 1,5-dichloropentane is controlled to be (2.01~2.05):1, thereby preparing the bisquaternary ammonium salt intercalating agent.

[0019] Preferably, the method for preparing the recyclable all-plastic composite toothpaste tube sheet in step three is as follows:

[0020] Step S5-1: Set the suitable all-plastic composite toothpaste tube sheet for recycling as a nine-layer co-extruded film, the film structure of which is as follows:

[0021] First layer: 5-15 parts by weight of polypropylene resin layer prepared from 100wt% polypropylene resin;

[0022] Second layer: 5-15 parts by weight of polypropylene resin layer prepared from 100wt% polypropylene resin.

[0023] The third layer: 3 to 8 parts by weight of an adhesive layer prepared from 100 wt% maleic anhydride-grafted polypropylene resin.

[0024] Fourth layer: 5-15 parts by weight of a barrier layer prepared from 95-99 wt% polypropylene resin and 1-5 wt% ethylene-vinyl alcohol copolymer resin;

[0025] Fifth layer: a barrier layer prepared from 90-99 wt% polypropylene resin and 1-10 wt% organic-inorganic composite modifier, 10-50 parts by weight;

[0026] Sixth layer: a barrier layer made of 95-99 wt% polypropylene resin and 1-5 wt% ethylene-vinyl alcohol copolymer resin, 5-15 parts by weight;

[0027] Seventh layer: 3-8 parts by weight of an adhesive layer prepared from 100 wt% maleic anhydride-grafted polypropylene resin;

[0028] Eighth layer: 5-15 parts by weight of a polypropylene resin layer prepared from 100 wt% polypropylene resin;

[0029] Ninth layer: 5-15 parts by weight of a polypropylene resin layer prepared from 100 wt% polypropylene resin;

[0030] Step S5-2: The raw materials from step S5-1 are fed into the hoppers of the nine screw extruders of the nine-layer co-extrusion film blow molding unit. After mixing, the molten resin is collected at the die head through the distributor, extruded and blow-molded through the die head, cooled and wound up to obtain a recyclable all-plastic composite toothpaste tube sheet with a thickness of 250-300μm.

[0031] Preferably, the mass ratio of intercalated modified graphene oxide to ethylene-vinyl alcohol copolymer in the organic-inorganic composite modifier is 1:(1-5);

[0032] Preferably, the mass ratio of the monoquaternary ammonium salt intercalator, the bisquaternary ammonium salt intercalator, and the graphene oxide in the intercalated modified graphene oxide is 1:1:(1-3).

[0033] Preferably, the thickness of the graphene oxide is 2-5 nm and the sheet diameter is 3-8 μm.

[0034] The application of a recyclable all-plastic composite toothpaste tube sheet prepared according to the above process in the field of toothpaste packaging.

[0035] Beneficial effects:

[0036] This invention synthesizes a single quaternary ammonium salt intercalating agent and a double quaternary ammonium salt intercalating agent, and simultaneously utilizes the single quaternary ammonium salt intercalating agent and the double quaternary ammonium salt intercalating agent to intercalate and modify graphene oxide by means of chemical bonding (reaction of silanol with hydroxyl, carboxyl, and epoxy groups), hydrogen bonding, and electrostatic interaction. Then, it is compounded with ethylene-vinyl alcohol copolymer to prepare an organic-inorganic composite modifier.

[0037] Organic-inorganic composite modifiers were added to a nine-layer co-extruded film made of single PP material, and a nine-layer co-extrusion blow molding process was used to prepare an all-plastic composite toothpaste tube sheet with a thickness of 250-300 μm. Experimental results showed that the all-plastic composite toothpaste tube sheet has excellent mechanical properties and barrier properties. Attached Figure Description

[0038] Figure 1 Synthetic route for monoquaternary ammonium salt intercalating agents;

[0039] Figure 2 The chemical structural formula of the bisquaternary ammonium salt intercalating agent;

[0040] Figure 3 Line graph showing the performance test results of an all-plastic composite toothpaste tube sheet suitable for recycling. Detailed Implementation

[0041] Example 1:

[0042] Preparation of monoquaternary ammonium salt intercalating agents, such as Figure 1 As shown, the preparation steps are as follows:

[0043] Step 1: A protic acid catalyst catalyzes the Mannich condensation reaction of paeonol containing α-H with formaldehyde and dimethylamine to generate a tertiary amine monomer.

[0044] The protic acid catalyst is one of sulfuric acid, hydrochloric acid, or phosphoric acid; hydrochloric acid was chosen for this experimental example.

[0045] Step 2: Based on the nucleophilic substitution mechanism, a quaternization reaction is carried out between the tertiary amine functional group of the tertiary amine monomer and the chlorine functional group of 3-chloropropyltrimethoxysilane to generate a monoquaternary ammonium salt intercalating agent.

[0046] The specific experimental steps for preparing the single quaternary ammonium salt intercalating agent are as follows:

[0047] Under nitrogen protection, 1.7 g of paeonol, 0.3 g of formaldehyde, 0.5 g of dimethylamine and 40 mL of anhydrous ethanol were added to a three-necked flask and stirred at room temperature until completely dissolved. Then, 5 drops of concentrated hydrochloric acid were slowly added dropwise to the three-necked flask, the temperature was raised to 85 °C and stirred under reflux for 4 h. After cooling to room temperature, the solvent was removed by rotary evaporation, filtered and dried under vacuum to obtain the tertiary amine monomer.

[0048] Under nitrogen protection, 1.1 g of tertiary amine monomer and 20 mL of cyclohexane were added to a three-necked flask, heated to 40 °C and stirred until completely dissolved. Then, 1.0 mL of 3-chloropropyltrimethoxysilane was added dropwise to the three-necked flask, and the reaction was carried out at 40 °C with stirring for 8 h. After cooling to room temperature, the solvent was removed by rotary evaporation, washed with ethyl acetate, and dried under vacuum to obtain a monoquaternary ammonium salt intercalating agent.

[0049] The 1H NMR characterization of the monoquaternary ammonium salt intercalating agent is as follows: 1 H NMR (CDCl3, 400MHz) δ: 0.84-0.98 (m, 2H), 1.75-1.82 (m, 2H), 3.30 (s, 6H), 3.34-3.38 (t, 2H), 3.49-3.52(t, 2H), 3.57(s, 9H), 3.79-3.83(t, 2H), 4.07(s, 3H), 6.48-7.27(m, 3H).

[0050] Example 2:

[0051] Preparation of bisquaternary ammonium salt intercalating agents, their chemical structural formulas are as follows: Figure 2 As shown, its preparation method is as follows: Based on the nucleophilic substitution mechanism, the tertiary amine functional group of the tertiary amine monomer undergoes a quaternization reaction with the chlorine functional group of 1,5-dichloropentane, and the molar ratio of the tertiary amine monomer to 1,5-dichloropentane is controlled to be (2.01~2.05):1, to generate a bisquaternary ammonium salt intercalating agent. The specific experimental steps are as follows: Under nitrogen protection, 2.2g of tertiary amine monomer and 30mL of cyclohexane are added to a three-necked flask, heated to 40℃ and stirred until completely dissolved. Then, 0.6mL of 1,5-dichloropentane is added dropwise to the three-necked flask, and the reaction is maintained at 40℃ with stirring for 12h. After cooling to room temperature, the solvent is removed by rotary evaporation, washed with ethyl acetate, and dried under vacuum to obtain the bisquaternary ammonium salt intercalating agent.

[0052] The 1H NMR characterization of the bisquaternary ammonium salt intercalating agent is as follows: 1 H NMR (CDCl3, 400MHz) δ: 1.60-1.65 (m, 6H), 3.31 (s, 12H), 3.33-3.37 (t, 4H), 3.52-3.56 (t, 4H), 3.74-3.78 (t, 4H), 4.04 (s, 6H), 6.49-7.37 (m, 6H).

[0053] Example 3:

[0054] The preparation method for modified graphene is as follows: Graphene oxide is modified by intercalation using a mono-quaternary ammonium salt intercalator and a bis-quaternary ammonium salt intercalator. The specific experimental steps are as follows: 3g of nano-graphene oxide powder, 80mL of anhydrous ethanol, and 20mL of deionized water are added to a beaker, sonicated for 30min, heated to 40℃ and stirred for 2h. Then, 1g of mono-quaternary ammonium salt intercalator and 1g of bis-quaternary ammonium salt intercalator are added to the beaker, and the mixture is heated to 70℃ and stirred for 4h. The mixture is then filtered while hot, washed with anhydrous ethanol until no precipitate is detected in silver nitrate solution, and vacuum dried to obtain the modified graphene.

[0055] Among them, the nano-graphene oxide powder was purchased from Jiangsu Xianfeng Nanomaterials Technology Co., Ltd., and its thickness was 2-5 nm and its sheet diameter was 3-8 μm.

[0056] The preparation method of the organic-inorganic composite modifier is as follows: Modified graphene is uniformly dispersed in an ethylene-vinyl alcohol copolymer matrix to prepare the organic-inorganic composite modifier. The specific experimental steps are as follows: 15g of ethylene-vinyl alcohol copolymer and 5g of modified graphene are added to a twin-screw extruder, and the organic-inorganic composite modifier is prepared by blending, melting, extruding and pelletizing through the twin-screw extruder.

[0057] The process parameters for the twin-screw extruder are set as follows: the temperatures in zones 1-3 are 160℃, 180℃, and 205℃, respectively, and the rotation speed is 50 r / min.

[0058] Example 3:

[0059] The preparation of a recyclable all-plastic composite toothpaste tube sheet includes the following steps:

[0060] Step 1: The suitable all-plastic composite toothpaste tube sheet for recycling is a nine-layer co-extruded film, with the following membrane structure:

[0061] First layer: 10 parts by weight of polypropylene resin layer prepared from 100wt% polypropylene resin;

[0062] Second layer: 10 parts by weight of polypropylene resin layer prepared from 100wt% polypropylene resin;

[0063] Third layer: 5 parts by weight of adhesive layer prepared from 100wt% maleic anhydride grafted polypropylene resin.

[0064] Fourth layer: 10 parts by weight of a barrier layer prepared from 97 wt% polypropylene resin and 3 wt% ethylene-vinyl alcohol copolymer resin;

[0065] Fifth layer: Barrier layer prepared from 95wt% polypropylene resin and 5wt% organic-inorganic composite modifier, 30 parts by weight;

[0066] Sixth layer: 10 parts by weight of a barrier layer prepared from 97 wt% polypropylene resin and 3 wt% ethylene-vinyl alcohol copolymer resin;

[0067] Seventh layer: 5 parts by weight of an adhesive layer prepared from 100 wt% maleic anhydride-grafted polypropylene resin.

[0068] Eighth layer: 10 parts by weight of polypropylene resin layer prepared from 100 wt% polypropylene resin;

[0069] Ninth layer: 10 parts by weight of polypropylene resin layer prepared from 100 wt% polypropylene resin;

[0070] Step 2: The raw materials from Step 1 are fed into the hoppers of the nine screw extruders of the nine-layer co-extrusion film blow molding unit. After mixing, the molten resin is collected at the die head through the distributor, extruded through the die head, blow molded, cooled, and wound up to obtain a 280μm thick all-plastic composite toothpaste tube sheet suitable for recycling.

[0071] The process parameters for the screw extruder corresponding to the polypropylene resin layer are set as follows: the temperatures of zones 1-3 are 120℃, 140℃, and 165℃, respectively; the runner temperature is 160℃; and the rotation speed is 30r / min.

[0072] The process parameters for the screw extruder corresponding to the adhesive layer are set as follows: the temperatures of zones 1-3 are 115℃, 145℃, and 160℃, respectively; the runner temperature is 150℃; and the rotation speed is 15r / min.

[0073] The process parameters for the screw extruder corresponding to the barrier layer are set as follows: the temperatures of zones 1-3 are 130℃, 160℃, and 180℃, respectively; the runner temperature is 175℃; and the rotation speed is 40r / min.

[0074] Among them, the polypropylene resin was purchased from Shanghai Qiaowei Chemical Technology Co., Ltd., and its grade is HJ4012; the maleic anhydride grafted polypropylene resin was purchased from Keais Chemical Co., Ltd., and its grade is B1; the ethylene-vinyl alcohol copolymer resin was purchased from Dongguan Kaixili Plastic Raw Materials Co., Ltd., and its grade is E105B.

[0075] Comparative example:

[0076] Preparation of sheet a: Only the organic-inorganic blend modifier was used to replace the organic-inorganic composite modifier in the all-plastic composite toothpaste tube sheet suitable for recycling, and the rest were the same. Sheet a was prepared and used as comparative example 1.

[0077] The preparation steps of the organic-inorganic blend modifier are the same as those of the preparation experiment of the organic-inorganic composite modifier. The only difference is that the intercalated modified graphene oxide is replaced with nano-graphene oxide powder.

[0078] Preparation of sheet b: Only the organic-inorganic composite modifier in the all-plastic composite toothpaste tube sheet suitable for recycling was replaced with ethylene-vinyl alcohol copolymer resin, and all other parts were the same. Sheet b was prepared and used as comparative example 1.

[0079] Performance testing:

[0080] (1) The oxygen transmission performance and water vapor transmission performance of the sample were tested according to GB / T 1038-2000 and GB / T 1037-2021 respectively. The specific test steps are as follows: Place the 30cm circular sample in a glass desiccator with an ambient temperature of 25℃ and anhydrous calcium chloride as desiccant for 72h. Then, use Y110 oxygen transmission tester and TC-03 water vapor transmission tester to test the barrier performance of the sample.

[0081] (2) The tensile strength of the sample was tested using an Instron 5565 universal tensile testing machine. The specific test steps are as follows: Fix the 150mm×20mm sample on the tensile testing machine and perform a tensile test at a tensile rate of 5mm / min. Record the longitudinal and transverse tensile strength of the sample.

[0082] The experimental results are shown in Table 1 and Figure 3 .

[0083] Table 1. Performance test results of all-plastic composite toothpaste tube sheets suitable for recycling.

[0084]

[0085] The hygienic performance of the samples was tested according to GB / T 5009.60-2003 "Analytical Methods for Hygienic Standards of Polyethylene, Polystyrene and Polypropylene Molded Products for Food Packaging". The experimental results confirmed that the all-plastic composite toothpaste tube sheet prepared by this invention can meet the hygienic standard requirements.

[0086] A comprehensive analysis of the above experimental results leads to the following conclusions:

[0087] (1) The addition of graphene oxide can enhance the barrier properties and mechanical properties of the sheet.

[0088] (2) The intercalation modification of graphene oxide by using mono-quaternary ammonium salt intercalating agent and bis-quaternary ammonium salt intercalating agent and then compounding it with ethylene vinyl alcohol copolymer has a significantly better effect on improving the barrier properties and mechanical properties of sheet than nano-graphene oxide powder without intercalation modification treatment.

Claims

1. A process for the preparation of a fully plastic composite toothpaste tube sheet suitable for recycling, characterized in that, It comprises the following steps: Step one: synthesis of monoquaternary ammonium salt intercalation agent and diquaternary ammonium salt intercalation agent; The chemical structural formula of the monoquaternary ammonium salt intercalation agent is: ； The chemical structural formula of the diquaternary ammonium salt intercalation agent is: ； Step two: based on covalent bond, hydrogen bond and electrostatic interaction, the monoquaternary ammonium salt intercalation agent and the diquaternary ammonium salt intercalation agent are used to intercalate and modify the graphene oxide to obtain intercalation modified graphene oxide; the intercalation modified graphene oxide is compounded with ethylene-vinyl alcohol copolymer to prepare an organic-inorganic composite modifier; The mass ratio of the intercalation modified graphene oxide and the ethylene-vinyl alcohol copolymer in the organic-inorganic composite modifier is 1:(1-5); The mass ratio of the monoquaternary ammonium salt intercalation agent, the diquaternary ammonium salt intercalation agent and the graphene oxide in the intercalation modified graphene oxide is 1:1:(1-3); Step three: the organic-inorganic composite modifier is added to the single polypropylene raw material, and a nine-layer co-extrusion blow molding process is adopted to prepare a full-plastic composite toothpaste tube sheet suitable for recycling.

2. A process for the preparation of a fully plastic composite toothpaste tube sheet suitable for recycling according to claim 1, characterized in that, The preparation method of the monoquaternary ammonium salt intercalation agent is: Step S2-1: a Mannich condensation reaction of paeonol containing α-H, formaldehyde and dimethylamine is catalyzed by a proton acid catalyst to prepare a tertiary amine monomer; Step S2-2: based on the nucleophilic substitution mechanism, a quaternary ammonium reaction of the tertiary amine functional group of the tertiary amine monomer and the chlorine functional group of 3-chloropropyl trimethoxysilane is carried out to prepare the monoquaternary ammonium salt intercalation agent.

3. A process for the preparation of a fully plastic composite toothpaste tube sheet suitable for recycling according to claim 2, characterized in that, The proton acid catalyst is one of sulfuric acid, hydrochloric acid and phosphoric acid.

4. A process for the preparation of a fully plastic composite toothpaste tube sheet suitable for recycling as claimed in claim 1, wherein, The preparation method of the diquaternary ammonium salt intercalation agent is: based on the nucleophilic substitution mechanism, a quaternary ammonium reaction of the tertiary amine functional group of the tertiary amine monomer and the chlorine functional group of 1,5-dichloropentane is carried out, and the molar ratio of the tertiary amine monomer to 1,5-dichloropentane is controlled to be (2.01-2.05):1 to prepare the diquaternary ammonium salt intercalation agent.

5. A process for the preparation of a fully plastic composite toothpaste tube sheet suitable for recycling as claimed in claim 1, wherein, The preparation method of the full-plastic composite toothpaste tube sheet suitable for recycling in step three is: Step S5-1: the full-plastic composite toothpaste tube sheet suitable for recycling is set as a nine-layer co-extrusion film, and the film structure is as follows: First layer: a polypropylene resin layer prepared by taking 100wt% polypropylene resin as raw material, 5-15 parts by weight; Second layer: a polypropylene resin layer prepared by taking 100wt% polypropylene resin as raw material, 5-15 parts by weight; Third layer: a bonding layer prepared by taking 100wt% maleic anhydride grafted polypropylene resin as raw material, 3-8 parts by weight; Fourth layer: a barrier layer prepared by taking 95-99wt% polypropylene resin and 1-5wt% ethylene-vinyl alcohol copolymer resin as raw material, 5-15 parts by weight; Fifth layer: a barrier layer prepared by taking 90-99wt% polypropylene resin and 1-10wt% organic-inorganic composite modifier as raw material, 10-50 parts by weight; Sixth layer: a barrier layer prepared by taking 95-99wt% polypropylene resin and 1-5wt% ethylene-vinyl alcohol copolymer resin as raw material, 5-15 parts by weight; Seventh layer: a bonding layer prepared by taking 100wt% maleic anhydride grafted polypropylene resin as raw material, 3-8 parts by weight; The eighth layer: a polypropylene resin layer prepared by using 100wt% polypropylene resin as raw material, 5-15 parts by weight; The ninth layer: a polypropylene resin layer prepared by using 100wt% polypropylene resin as raw material, 5-15 parts by weight; Step S5-2: each raw material in step S5-1 is respectively put into the hopper of the nine screw extruders of the nine-layer co-extrusion film blowing machine set, after mixing by stirring, the molten resin is converged at the machine head through the flow divider, extruded, blown, cooled and rolled through the die, to obtain a full-plastic composite toothpaste tube sheet with a thickness of 250-300μm suitable for recycling.

6. A process for the preparation of a fully plastic composite toothpaste tube sheet suitable for recycling as claimed in claim 1, wherein, The thickness of the graphene oxide is 2-5nm, and the flake diameter is 3-8μm.

7. A full plastic type composite toothpaste tube sheet suitable for recycling prepared by the process according to any one of claims 1-6, characterized by, Application of the full-plastic composite toothpaste tube sheet in the field of toothpaste packaging.

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