Diatomite odor absorption functional master batch as well as preparation method and application thereof

Abstract

The invention relates to the technical field of high polymer material modification and odor control, and discloses a diatomite odor absorption functional master batch as well as a preparation method and application thereof, and the master batch comprises the following components in parts by weight: 20-60 parts of calcined diatomite powder, 1-15 parts of a chemical absorption aid, 30-75 parts of carrier resin and 0.5-3 parts of a dispersion lubricating aid. According to the invention, calcined diatomite with a natural porous structure is used as a physical adsorption base material, and chemical absorption aids (such as guanidine carbonate, zinc diricinoleate and the like) with a non-porous structure are introduced, so that the adsorption effect is enhanced through a dual-action mechanism of combining physical adsorption and chemical locking; the efficient, broad-spectrum and irreversible removal of various volatile organic compounds such as aldehydes, amines and acids in the automobile interior plastic is realized. The master batch provided by the invention can effectively avoid the secondary release problem of a traditional physical adsorbent at high temperature, has good compatibility with a plastic matrix, does not influence the mechanical properties of the material, is low in cost, environment-friendly and efficient, and is especially suitable for automobile interior plastic products with strict requirements on odor.

Description

Technical Field

[0001] This invention relates to the field of polymer material modification and odor control technology, specifically to a functional masterbatch for adsorbing and eliminating volatile organic compounds in plastic products, and particularly to a diatomaceous earth odor absorption functional masterbatch with diatomaceous earth as the core, which has both physical adsorption and chemical locking functions, its preparation method, and its application in automotive interior plastic products. Background Technology

[0002] With the development of the automotive industry, in-cabin air quality (IAQ) has become one of the key indicators for measuring vehicle quality. Automotive interior components widely use polymer materials such as polypropylene (PP), polyethylene (PE), ABS resin, and polyurethane (PU) foam. During production, processing, and use, these materials continuously release volatile organic compounds (VOCs) such as aldehydes, ketones, benzene compounds, and amines, producing an unpleasant "new car smell" and posing a potential threat to the health of drivers and passengers.

[0003] Currently, the main methods for improving the odor of plastics include: 1. Source control method: Use low-VOC and low-odor raw materials for production, but the cost is high and it cannot completely eliminate the odor of thermal degradation during processing.

[0004] 2. Fragrance Masking Method: This method involves adding fragrances or odor-absorbing agents to plastics to mask the material's own odor with their strong aroma. Essentially, this method mixes and masks the smell, without truly eliminating or reducing harmful VOCs. Its drawbacks are significant: poor durability, as the fragrance evaporates over time; potential for more complex mixed odors that may cause discomfort to some individuals; and it only addresses the symptoms, not the root cause, failing to fundamentally solve the VOCs pollution problem.

[0005] 3. Direct Addition of Adsorbents: This method involves directly mixing powders such as activated carbon, molecular sieves, and zeolites into the plastic. This method has significant drawbacks: the powders exhibit poor dispersibility in non-polar plastic matrices, severely deteriorating the material's mechanical properties; more importantly, the physical adsorption forces (van der Waals forces) are weak, and under high-temperature conditions (such as 70-80℃ inside a car in summer), the adsorbed VOCs molecules are prone to desorption, causing "secondary pollution"; furthermore, it exhibits poor adsorption selectivity for VOCs molecules of different polarities, with limited adsorption effects on strongly polar and irritating molecules such as aldehydes and amines.

[0006] 4. Conventional Odor-Removing Masterbatch Method: To address the issue of uneven adsorbent dispersion, the industry has developed odor-removing masterbatches made by pre-dispersing adsorbents in a carrier resin. While this improves dispersibility, the core functional components are still mostly the aforementioned physical adsorbents, failing to fundamentally solve the problems of high-temperature desorption and adsorption selectivity. Alternatively, it relies on the synergistic effects of multiple porous materials, resulting in complex formulations and high costs.

[0007] In summary, current technologies lack an ideal solution for efficiently, broadly, and persistently absorbing and locking VOCs without affecting the mechanical properties of materials. Therefore, developing a novel and highly efficient deodorizing masterbatch has significant technological and market value. Summary of the Invention

[0008] The purpose of this invention is to overcome the defects and shortcomings of the prior art and provide a diatomaceous earth odor-absorbing masterbatch. This masterbatch achieves efficient, broad-spectrum, and irreversible removal of VOCs through a dual mechanism combining physical adsorption and chemical locking, especially with no risk of secondary release under high-temperature conditions, while also exhibiting good processing dispersibility and material compatibility.

[0009] To achieve the above-mentioned objectives, the present invention adopts the following technical solution: A diatomaceous earth odor-absorbing masterbatch, comprising the following components by weight: 20-60 parts calcined diatomaceous earth powder; 1-15 parts chemical absorption aid; 30-75 parts carrier resin; and 0.5-3 parts dispersing and lubricating aid. The chemical absorption aid is a non-porous compound that can chemically react or strongly complex with volatile organic compounds (VOCs).

[0010] Preferably, the chemical absorption aid is one or more of guanidine carbonate, zinc ricinoleate, and pentaerythritol. Guanidine carbonate can neutralize acidic substances and undergo addition reactions with aldehydes; zinc ricinoleate has a strong complexing ability for sulfur- and nitrogen-containing malodorous molecules; pentaerythritol can undergo acetal reactions with aldehydes.

[0011] Preferably, the calcined diatomaceous earth is calcined at a high temperature of 800-1200℃, and its particle size is 3000-8000 mesh. Calcination can remove organic impurities, open up pores, and increase specific surface area and adsorption capacity.

[0012] Preferably, the calcined diatomaceous earth is surface modified with a silane coupling agent, preferably γ-glycidoxypropyltrimethoxysilane (KH-560), to enhance its interfacial bonding with the resin matrix.

[0013] Preferably, the carrier resin is one of polypropylene (PP), linear low-density polyethylene (LLDPE), acrylonitrile-butadiene-styrene (ABS), ethylene-vinyl acetate copolymer (EVA), or styrene-based thermoplastic elastomer (SEBS) to ensure compatibility with the host plastic.

[0014] Preferably, the dispersing lubricant is one of polyethylene wax, stearic acid, or zinc stearate, to improve processing fluidity and component dispersibility.

[0015] This invention also provides a method for preparing the diatomaceous earth odor-absorbing masterbatch, comprising the following steps: S1. Raw material pretreatment: Dry the calcined diatomaceous earth powder at 100-130℃ for 2-6 hours; S2. High-speed mixing: Place the dried calcined diatomaceous earth powder, chemical absorption aid, carrier resin and dispersing lubricant into a high-speed mixer and mix for 3-15 minutes at a speed of 500-1500 rpm. S3. Melt extrusion granulation: The uniformly mixed material is fed into a twin-screw extruder and melt-blended, extruded, cooled, and granulated within a temperature range of 140-190℃ to obtain the functional masterbatch.

[0016] For the surface-modified masterbatch, before S1, there is also a step of surface modification of calcined diatomaceous earth: dispersing diatomaceous earth powder in a solvent, adding 1%-3% of its weight of silane coupling agent, reacting at 60-80℃ for 1-3 hours, and then filtering and drying.

[0017] This invention also claims protection for the application of the diatomaceous earth odor-absorbing masterbatch in the preparation of automotive interior plastic products. Compared with the prior art, this invention has the following significant advantages: 1. This invention achieves broad-spectrum removal of various polar and non-polar VOCs through the synergistic effect of physical adsorption of diatomaceous earth and chemical reaction of chemical absorption aids, transforming VOCs molecules into stable non-volatile substances, achieving "irreversible locking" and eliminating the risk of secondary release at high temperatures.

[0018] 2. This invention uses compounds such as guanidine carbonate as key chemical absorption aids, rather than traditional porous synergistic adsorbents such as molecular sieves and zeolites. Through a dual mechanism combining physical adsorption and chemical locking, it achieves efficient, broad-spectrum, and irreversible removal of various volatile organic compounds (VOCs) such as aldehydes, amines, and acids from automotive interior plastics.

[0019] 3. This invention uses masterbatch form and surface modification technology to ensure good dispersion and compatibility of functional components in the matrix, thereby maximizing the preservation of the mechanical properties and surface appearance of the product.

[0020] 4. The main raw material of this invention, diatomaceous earth, is a natural mineral with wide availability and low cost; the chemical additives are used in small quantities and are highly efficient, resulting in low overall cost and significant market economic value. Attached Figure Description

[0021] Figure 1 This is a process flow diagram of masterbatch preparation in an embodiment of the present invention. Detailed Implementation

[0022] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention. Example

[0023] Formula: 45 parts calcined diatomaceous earth (4000 mesh), 2 parts guanidine carbonate, 50 parts linear low-density polyethylene (LLDPE, MFR=25g / 10min), and 3 parts polyethylene wax.

[0024] Preparation process (one-step method): S1. Raw material pretreatment: Dry the diatomaceous earth in an oven at 120℃ for 4 hours.

[0025] S2. High-speed mixing: Add all components to a high-speed mixer and mix at 1000 rpm for 8 minutes.

[0026] S3. Melt extrusion granulation: Add the mixture to the twin-screw extruder and set the temperatures as follows: Zone 1 140℃, Zone 2 160℃, Zone 3 175℃, Zone 4 180℃, Zone 5 170℃, and die head 175℃. Screw speed 350 rpm.

[0027] The extruded strips are cooled with water, granulated, and vacuum-packed to obtain the finished masterbatch. Example

[0028] Formula: 50 parts calcined diatomaceous earth (6000 mesh), 8 parts zinc castor oil, 40 parts ethylene-vinyl acetate copolymer (EVA, VA content 18%), and 2 parts zinc stearate.

[0029] The preparation process is the same as in Example 1. Example

[0030] Formula: 45 parts calcined diatomaceous earth (5000 mesh), 1 part guanidine carbonate, 5 parts zinc ricinoleate, 47 parts homopolymer polypropylene (PP, MFR=40g / 10min), 1 part stearic acid, and 1 part polyethylene wax.

[0031] The preparation process is the same as in Example 1. Example

[0032] Formula: 55 parts of calcined diatomaceous earth (6000 mesh) surface-treated with silane coupling agent KH-560, 2 parts of guanidine carbonate, 38 parts of copolymer polypropylene (PP-Copo), 3 parts of pentaerythritol, and 2 parts of polyethylene wax.

[0033] Preparation process (two-step method): Surface modification: 100 parts of diatomaceous earth were ultrasonically dispersed in an ethanol / water mixed solvent, 1.5 parts of silane coupling agent KH-560 were added, and the mixture was reacted at 70°C for 2 hours. After filtration and washing, the mixture was dried at 110°C to obtain surface-modified diatomaceous earth powder.

[0034] The subsequent steps are the same as steps S1-S3 in Example 1.

[0035] To verify the effectiveness of the present invention, the following experiment was conducted:

[0036] Test subject: Comparative Example 1: High-odor recycled PP material.

[0037] Comparative Example 2: Add 5% commercially available activated carbon deodorizing masterbatch to Comparative Example 1.

[0038] Experimental groups 1 / 2 / 3: 3% of the masterbatch obtained in Examples 1 / 3 / 4 of the present invention was added to Comparative Example 1, respectively.

[0039] Test method: Referring to the odor test method of the automotive industry, the injection molded sample was heated at 80°C for 2 hours. After heating, the sampling bag was removed and cooled to room temperature. Professional evaluators scored the odor according to the 1-6 level standard.

[0040] Odor rating criteria (adapted from Q / JLYJ711061-2009): Grade 1: Odorless; Level 2: Has a slight odor, not noticeable; Level 3: A noticeable odor is present, but acceptable; Level 4: Has a noticeable odor, but is still acceptable; Level 5: Has a strong, unpleasant odor; Level 6: It has an extremely strong odor that is completely unbearable.

[0041] The test results are as follows:

[0042] The experimental results show that the odor level of the recycled PP raw material without any added deodorizing agent is as high as 4.8, far exceeding the standard. After adding commercially available activated carbon masterbatch, the odor level decreased, but it was still 3.6. Moreover, the evaluators reported that there was still a noticeable "stale" smell after high-temperature testing, which may be due to the desorption of some VOCs.

[0043] In contrast, the experimental groups that incorporated the functional masterbatch of this application all exhibited excellent deodorization effects. Only 3% of the addition was required to reduce the odor level to below 3.0, meeting the stringent requirements for automotive interior parts. The effects of Examples 3 (composite additive) and 4 (surface modification) were particularly outstanding, with odor levels reduced to 2.4 and 2.2, respectively.

[0044] Test results show that the functional masterbatch of the present invention can significantly reduce the odor level of plastics at low addition levels, and the effect is far superior to commercially available activated carbon masterbatch. Moreover, the composite additives and surface modification technology can bring a better synergistic deodorization effect.

[0045] To further quantify the deodorization effect of this invention, volatile organic compounds (VOCs) were detected in polyethylene (PE), PP / PE blend (70 / 30), and ABS plastic samples. Test conditions: The injection-molded samples were placed in a 1L sealed sampling bottle and heated at 80°C for 2 hours. Headspace gas was collected and analyzed using gas chromatography-mass spectrometry (GC-MS) to detect the concentrations of total VOCs and characteristic pollutants.

[0046] Test subject: Comparative Example A: Pure PE raw material; Comparative Example B: Add 5% commercially available activated carbon masterbatch; Comparative Example C: PP / PE blend raw materials; Comparative Example D: Add 5% commercially available activated carbon masterbatch; Comparative Example E: Pure ABS raw material; Comparative Example F: 5% commercially available activated carbon masterbatch added; Experimental Group A: PE raw material with 3% [Example 1] masterbatch added; Experimental Group B: PE raw material with 3% [Example 3] masterbatch added; Experimental Group C: PP / PE blend (70 / 30) with 3% [Example 1] masterbatch added; Experimental group D: PP / PE blend (70 / 30) with 3% [Example 3] masterbatch added; Experimental Group E: ABS plastic with 3% [Example 1] masterbatch added; Experimental group F: ABS plastic with 3% [Example 3] masterbatch added.

[0047] The test results are as follows: 1. The test results for PE plastic are shown in Table 1:

[0048] 2. The test results of PP / PE (70 / 30) blended plastics are shown in Table 2:

[0049] The test results for ABS plastic are shown in Table 3:

[0050] The experimental results show that, using the VOC emissions from PE plastic, PP / PE blends, and ABS raw materials without any added odor-removing agents as a standard, the addition of commercially available activated carbon masterbatch reduced VOC emissions, achieving a removal rate of approximately 30%. In contrast, the experimental groups that added the functional masterbatch from this application all demonstrated excellent VOC emission reduction effects. Only 3% of the masterbatch is needed to increase the VOC removal rate to over 60%, meeting the stringent requirements for automotive interior parts.

[0051] Test results show that the functional masterbatch of the present invention can significantly reduce the volatilization of VOCs in plastics even at low addition levels, with an effect far superior to commercially available activated carbon masterbatch. Furthermore, the composite additives and surface modification technology can bring about a more excellent synergistic deodorization effect.

[0052] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0053] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A diatomaceous earth odor-absorbing masterbatch, characterized in that, By weight, it includes the following components: 20-60 parts calcined diatomaceous earth powder; 1-15 parts chemical absorption aid; 30-75 parts of carrier resin; Dispersing lubricant 0.5-3 parts; The chemical absorption aid is a non-porous compound that can chemically react with or strongly complex with volatile organic compounds.

2. The diatomaceous earth odor-absorbing masterbatch according to claim 1, characterized in that, The chemical absorption aid is one or more of guanidine carbonate, zinc ricinoleate, and pentaerythritol.

3. The diatomaceous earth odor-absorbing masterbatch according to claim 1, characterized in that, The calcined diatomaceous earth is diatomaceous earth that has been calcined at a high temperature of 800-1200℃, and its particle size is 3000-8000 mesh.

4. The diatomaceous earth odor-absorbing masterbatch according to claim 1 or 3, characterized in that, The calcined diatomaceous earth is surface modified with a silane coupling agent.

5. The diatomaceous earth odor-absorbing masterbatch according to claim 4, characterized in that, The silane coupling agent is γ-glycidoxypropyltrimethoxysilane.

6. The diatomaceous earth odor-absorbing masterbatch according to claim 1, characterized in that, The carrier resin is one of polypropylene, linear low-density polyethylene, acrylonitrile-butadiene-styrene, ethylene-vinyl acetate copolymer, or styrene-based thermoplastic elastomers.

7. The diatomaceous earth odor-absorbing masterbatch according to claim 1, characterized in that, The dispersing lubricant is one of polyethylene wax, stearic acid, or zinc stearate.

8. A method for preparing a diatomaceous earth odor-absorbing masterbatch as described in any one of claims 1-7, characterized in that, Includes the following steps: S1. Raw material pretreatment: Dry the calcined diatomaceous earth powder at 100-130℃ for 2-6 hours; S2. High-speed mixing: Place the dried calcined diatomaceous earth powder, chemical absorption aid, carrier resin and dispersing lubricant into a high-speed mixer and mix for 3-15 minutes at a speed of 500-1500 rpm. S3. Melt extrusion granulation: The uniformly mixed material is fed into a twin-screw extruder and melt-blended, extruded, cooled, and granulated within a temperature range of 140-190℃ to obtain the functional masterbatch.

9. A method for preparing a diatomaceous earth odor-absorbing masterbatch according to claim 8, characterized in that, Before S1, there is also a step of surface modification of calcined diatomaceous earth: diatomaceous earth powder is dispersed in a solvent, 1%-3% of its weight of silane coupling agent is added, and the mixture is reacted at 60-80℃ for 1-3 hours, followed by filtration and drying.

10. The application of a diatomaceous earth odor-absorbing masterbatch as described in any one of claims 1-7 in the preparation of automotive interior plastic products.

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