Low-VOC (volatile organic compound) environment-friendly foaming PVC (polyvinyl chloride) profile and preparation method thereof

Abstract

The invention discloses a low-VOC (volatile organic compound) environment-friendly foaming PVC (polyvinyl chloride) profile and a preparation method, and relates to the technical field of building plastic profiles, the profile faces door and window joints in contact with silicone sealants (acetic acid type and oxime type) and polyurethane foaming agents, the profile adopts a three-layer structure: a surface layer is a sol-gel silica anti-infiltration layer; the near surface is a reaction-adsorption transition layer and contains beta-cyclodextrin grafted aminated silicon dioxide, zinc ion exchange zeolite and epoxy polyhedral oligomeric silsesquioxane; the foam core is a low-source foaming system and is matched with low-migration plasticizing lubrication; external acetic acid, oxime and tertiary amine are subjected to peak clipping and in-situ fixation in a epidermis-foam core transition zone through side feeding directional enrichment and plasma coating; under the conditions of ISO 16000-9 and VDA278, delta TVOC is less than or equal to 30 mu g / m, acetic acid, diacetylmonoxime and tertiary amine are reduced by more than or equal to 80%, more than or equal to 75% and more than or equal to 70%, and the adhesion and atomization performance is kept.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of building plastic profiles, in particular to a low-VOC environmentally friendly foamed PVC profile and a preparation method thereof. BACKGROUND

[0002] Foamed polyvinyl chloride profiles are widely used in door and window, curtain wall, fabricated interior, and keel, frame, bead, etc. of vehicle interior, and are generally in long-term face-to-face contact with silicone sealant (acetic acid curing type, neutral oxime type) or single-component polyurethane foaming agent during on-site installation. The existing technology mainly reduces the material's own emission by selecting low-volatile formula, conventional calcium-zinc stabilizing system, and general foaming and skin densification, but lacks effective control of the interaction emission induced by "different material contact": acetic acid released by acetic acid type silicone can enter the bubble wall under the condition of skin swelling, and react with fillers and residual chlorides; butanone oxime released by oxime type silicone and tertiary amine released by polyurethane curing are prone to accumulate at the skin-bubble core interface, and migrate directionally through micro-cracks and connected holes. Driven by solar heating, hot welding processing, and humidity fluctuation, the interface area undergoes a "swelling-diffusion-desorption" cycle, and after installation, thermal activation secondary peaks, local odor at the end surface, and long tail release often occur.

[0003] In addition, organic solvents and tackifying resins in the sealant can extract a small amount of plasticizers and oligomers from the profile surface layer, forming a new migration source; and the nanocracks generated by the mismatch of skin and bubble core thermal expansion also constitute a "channel effect" along the end surface, further amplifying the release fluctuation. The current practice relies more on sealant end selection or ventilation dilution, and it is difficult to obtain stable and reproducible results under the evaluation of ISO 16000-9, VDA278, DIN 75201, etc.

[0004] Therefore, in the assembly scene of foamed polyvinyl chloride profiles in contact with silicone sealant or polyurethane foaming agent, how to inhibit the "interface-driven, location-dependent" penetration and chemical-induced emission of external acetic acid, oxime, and tertiary amine; specifically, to prevent their accumulation in the skin-bubble core transition zone and migration along the connected channels, avoid the secondary peaks and long-term tail gas triggered by temperature and humidity and thermal activation, while not reducing the interface matching required for node bonding and sealing. SUMMARY

[0005] (I) Technical problems solved In view of the deficiencies of the prior art, the present application provides a low VOC environment-friendly foamed PVC profile and a preparation method, which comprises a three-layer structure: the skin is a sol-gel silica anti-infiltration layer; the near-surface is a reaction-adsorption transition layer containing beta-cyclodextrin grafted aminosilica, zinc ion exchanged zeolite and epoxy cage-like silsesquioxane; the bubble core is a low-source foaming system and is matched with a low-migration plastic lubricant; through side-feeding directional enrichment and plasma coating, external acetic acid, oxime and tertiary amine are cut off and fixed in place in the skin-bubble core transition zone; under the conditions of ISO16000-9 and VDA278, the ΔTVOC is ≤30 μg / m³, the acetic acid, butanone oxime and tertiary amine are reduced by ≥80%, ≥75% and ≥70% respectively, and the bonding and atomization properties are maintained; thereby the technical problems recorded in the background art are solved.

[0006] (Two) Technical solutions To achieve the above object, the present application is realized by the following technical solutions: A low VOC environment-friendly foamed PVC profile, comprising an L1 skin anti-infiltration layer, an L2 near-surface reaction-adsorption transition layer and an L3 bubble core body phase arranged in sequence from outside to inside, wherein: L1 is a dense coating layer formed by sol-gel of 3-(methacryloxy)propyltrimethoxysilane, vinyltrimethoxysilane, n-tetraethoxysilane and n-octyltrimethoxysilane, and compounded with 20-40 nm nano-sized silica dioxide, with a thickness of 0.8-2.0 μm, a surface energy of 24-28 mN / m, and no fluorine-containing structure; L2 is located in a band-shaped area 10-30 μm away from the surface, containing beta-cyclodextrin grafted aminosilica, zinc ion exchanged zeolite (13X or 5A, zinc exchange degree ≥60%), octa-functional epoxy cage-like silsesquioxane and refined layered double hydroxide, the volume fraction of L2 in the band is 2-3 times of the bulk phase and the enrichment ratio is ≥2; L3 is a PVC bubble core body phase with a density of 0.55-0.65 g / cm³, the foaming system is a combination of controllable release sodium bicarbonate organic acid composite microcapsules and expandable polymer microspheres, and the PVC resin is composed of 80-90 parts of K value 66-68 resin and 10-20 parts of K value 57-60 resin.

[0007] Further, the working liquid solid content of the L1 coating layer is 20-25%, and the coating dry weight is 0.6-1.2 g / m²; The precursor sol is compounded by n-tetraethoxysilane: 3-(methacryloxy)propyltrimethoxysilane: vinyltrimethoxysilane: n-octyltrimethoxysilane in a mass ratio of 1.0:1.0:0.5:0.10, and mixed with 20-40 nm nano-sized silica dioxide in a mass ratio of 2:1.

[0008] Further, the ratio of the L2 near-surface reaction adsorption transition layer is: β-cyclodextrin grafted aminosilica 1.0-1.5 phr, zinc ion exchanged zeolite 0.8-1.2 phr, eight functional group epoxy cage silsesquioxane 0.25-0.45 phr, and refined layered double hydroxide 0.3-0.6 phr.

[0009] Further, the enrichment of L2 is determined by cross-section micro-infrared / spectroscopy / time-of-flight secondary ion mass spectrometry with a 5 μm step in the thickness direction, and the signal intensity of the functional particles in the 10-30 μm band from the surface is ≥2 times that of the bulk phase.

[0010] Further, the foaming system of L3 includes controllable release sodium bicarbonate organic acid composite microcapsules 0.7-1.2 phr (shell material: ethyl cellulose and acrylic copolymer, onset temperature 165±5℃) and expandable polymer microspheres 0.6-1.0 phr (acrylonitrile-methyl methacrylate shell, initial expansion temperature 140-150℃), and contains flaky talc 0.2-0.4 phr and organically modified montmorillonite 0.15-0.30 phr.

[0011] The preparation method of the low-VOC environmentally friendly foamed PVC profile includes, A) dry mixing according to the formula and incorporating controllable release sodium bicarbonate organic acid composite microcapsules and expandable polymer microspheres; B) double screw extrusion foaming molding, setting temperature zones 150 / 160 / 165 / 170 / 170 / 165℃, die head 165±5℃, vacuum exhaust ≥−0.08 MPa, to obtain a bubble core profile with a density of 0.55-0.65 g / cm³; C) adding 60% of the transition layer compounded particles near the side feed port of the die head, and injecting eight functional group epoxy cage silsesquioxane dispersion through a gear pump, so that β-cyclodextrin grafted aminosilica and zinc ion exchanged zeolite are enriched in the 10-30 μm band from the surface, with an enrichment ratio ≥2; D) corona or plasma activation of the outer surface at 40-60 watts·minutes / square meter, coating a sol composed of 3-(methacryloyloxy)propyltrimethoxysilane, vinyltrimethoxysilane, n-tetraethoxysilane, and n-octyltrimethoxysilane, and nanosilica, drying at 60-80℃ hot air for 30-90 seconds, curing at 23-30℃, relative humidity 50-70% for 48 hours, to obtain an L1 skin with a thickness of 0.8-2.0 μm and a surface energy of 24-28 mN / m.

[0012] Further, the double screw end section is equipped with only two groups of 30° low-strength kneading blocks and conveying elements, the specific energy of the end section is ≤0.08 kWh / kg; the first exhaust port is at normal pressure, and the vacuum degree of the second exhaust port is ≥-0.08 MPa; the rotation speed of the side-feeding metering screw is 120-130% of that of the main machine, and the average melt residence time in the near-wall flow area is 20-40 seconds.

[0013] Further, the L2 near-surface enrichment is achieved by micro-layer co-extrusion or annular melt injection: a 2-channel micro-layer splitter is connected in series before the die to incorporate a high-concentration small material containing D2 at a muscle layer flow rate of 3-6% to form a 12-25 μm skin layer, or a 0.3-0.5 mm annular injection slot is opened in the transition section of the die head to inject a 0.8-1.2 kg / h annular injection to form an annular near-surface band.

[0014] Further, the interval between activation and coating is ≤2 minutes; after coating, hot air drying at 60-80°C for 30-90 seconds, and then standing in an environment of 23-30°C and a relative humidity of 50-70% for 48 hours for wet curing; or a UV curing scheme is adopted: 200-400 mJ / cm² of UV energy is applied under the condition of 1% photoinitiator, and curing is performed for 4-6 hours.

[0015] Further, a 5-8 mm non-coated area is reserved at the joint / coupling position where strong adhesion with the sealant is required, or a polarity-enhanced variant is used (3-aminopropyl triethoxysilane is added to the working solution at 0.05-0.10 parts by mass, and the vinyl trimethoxysilane is adjusted to 0.3 parts by mass), and the surface energy of the corresponding area is 30-32 mN / m, and the surface energy of the remaining exposed surface is 24-28 mN / m.

[0016] (III) Beneficial Effects The present application provides a low-VOC environmentally friendly foamed PVC profile and a preparation method, which have the following beneficial effects: Through the localization of the skin anti-infiltration layer-near-surface reaction / adsorption transition layer-foam core low-source buffer layer, the swelling, penetration and migration of external small molecules such as silicone acetate, neutral oxime and polyurethane tertiary amine at the interface are significantly reduced, the total volatile amount and characteristic peak after contact are significantly reduced, and the secondary release caused by heat stimulation is inhibited; at the same time, the surface energy and mechanics required for node adhesion are retained, and no side effects such as atomization, dusting or weld angle embrittlement are introduced.

[0017] The given components and process parameters have engineering rationality: the skin thickness of 0.8-2.0 microns matches the production capacity and coating limit of sol-gel curing and online plasma activation; the directional enrichment of the transition layer of 10-30 microns can be realized by double screw side feeding and near-wall flow, which can capture acetate, oxime and tertiary amine in the initial diffusion section without affecting the overall toughness.

[0018] The mass fraction of the β-cyclodextrin grafted silica, zinc exchanged zeolite and epoxide cage silsesquioxane is controlled at 2.5-3.5 parts per hundred parts of resin, which meets the upper limit of extrusion dispersion and color phase controllability; the dosage (about 3 parts) of calcium-zinc, layered double hydroxide and reactive phosphite is in the tin-free, low odor stable window; the gas yield, initiation temperature and die temperature zone of the microcapsule and polymer microsphere are connected, so that fine and dense pores can be obtained and nitrogen-containing by-products can be avoided; and the total amount (about 14 parts) of the polymeric plasticizer and the low-migration lubricant meets the balance of the welding, falling hammer and long-term migration limit values.

[0019] In summary, the parameter interval and manufacturing means are consistent with the existing equipment capacity, material physical properties and diffusion-adsorption-reaction mechanism, and have reproducibility and scalability. BRIEF DESCRIPTION OF DRAWINGS

[0020] Figure 1 A flowchart of the preparation method of the low-VOC environmentally friendly foamed PVC profile of the present application is shown. DETAILED DESCRIPTION

[0021] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present application.

[0022] Please refer to Figure 1 The present application provides a low-VOC environmentally friendly foamed PVC profile and a preparation method thereof, which comprises, Comprising the following components: I. Overall design and hierarchical function L1 skin anti-infiltration layer (0.8-2.0 microns, preferably 1.2 microns) The ultrathin dense layer composed of organic-inorganic silicon-oxygen network and nanosilica reduces the solubility and diffusion coefficient of external small molecules at the contact surface, and controls the surface energy window (24-28 millinewtons per meter) to meet the bonding requirements of sealant.

[0023] L2 near-surface reaction-adsorption transition layer (10-30 microns, preferably 20 microns) The combination of β-cyclodextrin grafted aminosilica, zinc ion exchanged zeolite and octafunctional epoxide cage silsesquioxane realizes the in-situ capture or structural fixation of external small molecules such as acids, ketones, acyl isoxazoles and tertiary amines. This layer is enriched near the surface in the melt through secondary feeding; Micro-layer co-extrusion: 2-channel skin / core split-block in-line before die, high-concentration small D2 charge (D2 15-25 phr, PVC 75-85 phr, melt index matched to main body) at 3-6% skin layer flow rate, target skin thickness 12-25 pm; this can physically solidify the targeted enrichment into a thin skin layer.

[0024] Annular melt-injection: 0.3-0.5 mm annular injection slit in head-die transition, D2 concentrated melt injected at 0.8-1.2 kg / h by gear pump to form an annular near-surface band.

[0025] Screw configuration: only 30° low-intensity kneading blocks in two groups + conveying elements in the last section, 60° / 90° high-intensity kneading prohibited; specific energy in the last section ≤ 0.08 kWh / kg. Cross-sectional micro-FTIR / EDS / ToF-SIMS quantification at 5 pm steps along the thickness direction, with enrichment ratio ≥ 2 defined as passing; 3 batches of repeated data (average thickness of enrichment band ± standard deviation) are given.

[0026] Oximes are physically constrained by β-cyclodextrin inclusion + near-surface network densification; epoxide cage silsesquioxane is used to open ring with amino-silica / micro-carboxylic acid to build a nano-network, indirectly reducing the diffusion coefficient of oximes; epoxide functionality is limited to ≥ 6; the degree of ring opening with amine / carboxyl sites is 20-40% (calculated by epoxide titration); L3 foam core phase (density 0.55-0.65 g / cm3) Low by-product foaming and low-migration plasticizing-lubricating system is used to reduce the release source of the body and provide micro-structural cushioning while ensuring mechanical properties and welding corner processability.

[0027] II. Formulation and Components The following ranges are recommended feasible windows, and the preferred values are the nominal points preferred for implementation. If not specified, all are calculated in L3 matrix by phr; L1 is the coating / co-extrusion layer, and the formulation is given separately.

[0028] Component A, PVC resin matrix (100 phr) Specifically, the resin molecular weight and K value: K value 66-68 resin: 80-90 parts (preferably 85 parts); K value 57-60 resin: 10-20 parts (preferably 15 parts) After combination, the melt strength, controllability of foaming, and thermal history stability can be considered.

[0029] Particle size and cleanliness: Median particle size D50: 120-160 pm (preferably 140 pm); vinyl chloride monomer residue ≤ 0.5 mg / kg; moisture ≤ 0.2 mass percent.

[0030] Component B, stabilizing and acid suppression system (total amount 2.5-3.8 phr; preferably 3.1 phr) Specifically, it includes calcium-zinc organic salt complex stabilizer: 1.5-1.9 phr (preferably 1.6 phr); zinc / calcium molar ratio about 1 / 2; free fatty acid mass fraction ≤1%; reactive phosphite: 0.3-0.5 phr (preferably 0.35 phr); phosphorus content 7.5-9.0 mass percent; acid value ≤0.5 mg KOH / gram; low volatile grade; Magnesium-aluminum-carbonate layered double hydroxide (LDH): 0.6-1.0 phr (preferably 0.8 phr); magnesium / aluminum atomic ratio about 2.5; average particle size 0.5-0.8 microns; specific surface area ≥50 m2 / g; imidazolium salt loaded mesoporous silica acid capture agent: 0.2-0.35 phr (preferably 0.25 phr); carrier pore size 3-5 nm, specific surface area ≥600 m2 / g; Imidazolium salt (such as 1-ethyl-3-methyl imidazole methyl sulfate or bicarbonate) loading 20-25 mass percent; water content ≤1.0 mass percent. Ionic liquid selection anion is methyl sulfate / hydrogen phosphate / bicarbonate, not using tetrafluoroborate / hexafluorophosphate; 105℃×24h weight loss ≤0.5%; VDA278 (90℃) increment ≤10 μg / g; when used with layered double hydroxide, total alkali equivalent amount ≤0.02 mol / kg formulation, to avoid excessive free alkali.

[0031] Component B, stabilizing and acid suppression system cooperates with component D to preferentially neutralize external acidic or acidification precursors, reducing acid catalyzed side reactions under heat / shear.

[0032] Component C, foaming and nucleation (total amount 1.8-3.0 phr; preferably 2.4 phr) Specifically, it includes controllable release sodium bicarbonate-organic acid complex microcapsule: 0.7-1.2 phr (preferably 0.9 phr); organic acid should be selected from citric acid or tartaric acid; shell material is ethyl cellulose and acrylic copolymer complex (shell content 15-25 mass percent), softening temperature ≥130℃; initial expansion temperature 165±5℃, gas yield ≥90 ml / 100 g; ash content control ≤2 mass percent.

[0033] Expandable polymer microspheres: 0.6-1.0 phr (preferably 0.8 phr); shell material is acrylonitrile-methyl methacrylate copolymer; inner core is low boiling point hydrocarbon; initial expansion temperature 140-150℃; volume distribution is uniform, D50=12-18 microns.

[0034] Nucleating agent complex: Talcum: 0.2 - 0.4 phr (preferably 0.3 phr), average particle size 0.7 - 1.0 microns; organically modified montmorillonite: 0.15 - 0.30 phr (preferably 0.2 phr), cation exchange capacity 90 - 120 meq / 100 g, loss on drying < 2%.

[0035] The combination can reduce nitrogen-containing by-products, obtain fine and slightly flat cells, shorten the effective penetration path of foreign small molecules, and improve the toughness of the cell wall.

[0036] Component D, VOC suppression and interface interception network Specifically, it is divided into skin coating (for L1), transition layer (for L2) and bulk optional adsorption module (for L3); D1 (for L1 skin, coating amount 0.6 - 1.2 g / m2; preferably 0.9 g / m2); Specifically, it includes a sol-gel precursor combination: 3-(methacryloyloxy)propyltrimethoxysilane: 0.8 - 1.2 parts by mass (relative to TEOS in the formula, preferably 1.0); vinyltrimethoxysilane: 0.4 - 0.7 parts by mass (preferably 0.5); tetraethoxysilane (TEOS): 1.0 parts by mass (reference); n-octyltrimethoxysilane: 0.05 - 0.15 parts by mass (preferably 0.10), used to adjust surface energy and does not contain fluorine structure; Solvent and catalyst: Deionized water / anhydrous ethanol volume ratio 4 / 1; catalytic use of trace hydrochloric acid, final mixed solution pH = 2.5 - 3.5; Complexing stabilizer can use acetylacetone (silane molar ratio 1 - 2%).

[0037] Nanosilica dispersion: Particle size 20 - 40 nm, surface pre-modified with 3-(methacryloyloxy)propyltrimethoxysilane; solid content 20 - 30 mass%; before coating, compound with precursor sol at a mass ratio of 1 / 3 - 1 / 1, final machine solid content 20 - 25%.

[0038] Curing conditions: After coating, dry with hot air at 60 - 80 degrees Celsius for 30 - 90 seconds; stand still in an environment of 23 - 30 degrees Celsius and relative humidity of 50 - 70% for 48 hours to complete condensation; film thickness 0.8 - 2.0 microns (preferably 1.2 microns), surface energy controlled at 24 - 28 mN / m.

[0039] Note: For local areas requiring strong adhesion, the D1 can not be applied to form an adhesion window, width suggested 5-8mm; or a polarity enhanced variant of D1 is used (increasing 3-aminopropyl triethoxysilane 0.05-0.10 parts by mass), surface energy adjusted to 30-32mN / m. A 5-8mm uncoated area or a polarity enhanced version (surface energy 30-32mN / m) is reserved at the overlap / lap site where adhesion is required; the rest of the exposed surface uses L1 with a surface energy of 24-28mN / m.

[0040] Inspection alignment: lap shear strength is tested and evaluated only in the adhesion window area; contact angle and surface energy are measured on the exposed surface.

[0041] D2 (for L2 transition layer, total amount 2.5-3.5phr; preferably 3.0phr) Specifically, beta-cyclodextrin grafted aminosilica: 1.0-1.5phr (preferably 1.2phr); support specific surface area ≥ 150 square meters per gram, average particle size 0.2-0.5 microns; surface primary amine group density 1.2-1.6 millimoles per gram; beta-cyclodextrin loading 0.3-0.5 millimoles per gram; moisture ≤ 1.0 mass percent, free epoxy residue ≤ 0.1 mass percent (see later for preparation method of key intermediate); Zinc ion-exchanged zeolite (13X or 5A): 0.8-1.2phr (preferably 1.0phr); zinc exchange degree ≥ 60%; micropore volume 0.25-0.35 cubic centimeters per gram; average particle size 1-3 microns; sodium content ≤ 0.5 mass percent; ignition loss ≤ 3 mass percent; octafunctional epoxide cage silsesquioxane: 0.25-0.45phr (preferably 0.35phr); effective epoxy equivalent weight 500-800 grams per equivalent; particle size nano-submicron level, pre-dispersed with a small amount of plasticizer is recommended.

[0042] Refined layered double hydroxide: 0.3-0.6phr (preferably 0.45phr), as an acid buffer and structural support to keep the transition layer microscopically stable. Thus, by means of twin-screw side feeding, the local volume fraction of D2 within a 10-30 micron band from the surface reaches 2-3 times the bulk phase.

[0043] D3 (for L3 bulk phase, optionally 0.3-0.8phr; preferably 0.5phr) Specifically, mesoporous silica and light-colored activated carbon are compounded into a powder: total amount 0.3-0.8phr (preferably 0.5phr); mesopore diameter 6-12 nanometers; activated carbon iodine value 700-900 milligrams per gram; mass ratio of the two 1 / 1-3 / 1. As a low-dose buffer bank in the bulk, it reduces long-term trailing release.

[0044] E: compatible, toughening and low-migration lubricity (total 10-16 phr; preferably 13.4 phr) Specifically, acrylate processing aid: 1.0-1.5 phr (preferably 1.2 phr), glass transition temperature 95-105 degrees Celsius; butyl methacrylate-styrene-acrylonitrile core-shell structure toughener (also known as MBS): 6.0-8.0 phr (preferably 7.0 phr), average particle size of rubber core 70-90 nanometers; Polymeric aliphatic dibasic acid ester plasticizer: 2.5-4.0 phr (preferably 3.2 phr), number average molecular weight 3000-6000, acid value ≤1.0 mg KOH / g, 24-hour weight loss at 120 degrees Celsius ≤0.2 mass percent; as an equivalent replacement: polymeric citrate (number average molecular weight 4000-8000), used when encountering more stringent migration control.

[0045] Epoxidized vegetable oil (epoxidized soybean oil or epoxidized rapeseed oil): 1.5-2.2 phr (preferably 1.8 phr), epoxy value 6.4-7.0 mass percent; polymeric ester wax external lubricant: 0.3-0.5 phr (preferably 0.4 phr); oxidized polyethylene wax internal lubricant: 0.3-0.5 phr (preferably 0.4 phr).

[0046] III. Typical Formulation (can be directly sampled) Example 1 (general type, containing L1 coating) A: PVC resin (K66-68: 85 parts; K57-60: 15 parts); B: calcium-zinc stabilizer 1.6; reactive phosphite 0.35; LDH 0.8; imidazolium salt @ mesoporous silica 0.25; C: controlled-release sodium bicarbonate-organic acid microcapsule 0.9; expandable microsphere 0.8; talc 0.3; organic montmorillonite 0.2; D2 (added near the surface): β-cyclodextrin grafted aminosilica 1.2; zinc-exchanged zeolite 1.0; octafunctional epoxide cage-like silsesquioxane 0.35; fine LDH 0.45; D3 (optional in the bulk phase): mesoporous silica / activated carbon compound 0.5; E: acrylate processing aid 1.2; core-shell structure toughener 7.0; polymeric aliphatic dibasic acid ester 3.2; epoxidized vegetable oil 1.8; polymeric ester wax 0.4; oxidized polyethylene wax 0.4; L1 coating D1: prepare sol according to D1 formulation, coating amount 0.9 g / m2, thickness about 1.2 microns.

[0047] Example 2 (special for bonding sensitive nodes, local bonding window) The bulk formulation is the same as in Example 1; L1 coating is not applied (window 5-8mm wide) in areas requiring strong adhesion to sealant, or a polar enhanced variant is used (3-aminopropyltriethoxysilane increased to 0.10 parts by mass, vinyl silane decreased to 0.3 parts by mass), otherwise same.

[0048] Example 3 (light color high appearance requirement) Activated carbon in D3 is reduced to 0.2 phr and mesoporous silica is increased to 0.6 phr; Nucleating agent talc is adjusted to 0.2 phr; Same as Example 1 otherwise.

[0049] Preparation procedure is as follows: phr in the formula is the amount of addition per 100 parts of PVC (parts by mass). Taking the base batch PVC = 100 kg as an example, the actual mass (kg) of an additive = phr of the additive ÷ 100 × 100 kg. For example: 1.60 phr of calcium-zinc stabilizer, corresponding to weighing 1.60 kg.

[0050] 0. Equipment and environmental preparation Environmental conditions: temperature 20-28 degrees Celsius, relative humidity 45-65% in compounding and extrusion workshop. Relative humidity 50-70% in coating and moisture curing area.

[0051] Main equipment: high-speed mixer (effective volume ≥ 200 liters, maximum speed ≥ 1200 rpm, with automatic discharge); co-rotating twin-screw extruder (length-diameter ratio ≥ 40:1, at least one side feeding port and one vacuum exhaust port; equipped with 0.1-0.2 megapascal vacuum system); profile die and vacuum sizing tank, traction machine, cutting machine; side-feeding metering screw and powder feeder (accurate to ±1%); corona or plasma surface activation device (power density adjustable); coating device (comma doctor blade or gravure roll, metering accuracy controllable), 60-80 degrees Celsius hot air curing channel; fluidized bed spraying or spray drying equipment (for microcapsule preparation); filtration and drying equipment: plate and frame filter, vacuum oven.

[0052] Raw material pretreatment: all powdered raw materials (including polyvinyl chloride resin, layered double hydroxide, talc powder, zeolite, etc.) are sieved using an 80-120 mesh screen to remove lumps; polyvinyl chloride resin, layered double hydroxide, zeolite, etc. are pre-dried in a 60 degrees Celsius hot air circulation oven for 4-6 hours, with a target moisture content of ≤0.2% (confirmed by Karl Fischer method); flammable solvents such as ethanol and silane precursors used for coating are stored in an explosion-proof area, grounded to prevent static electricity.

[0053] 1. As an example, a typical one-pot batch weighing list (for this general formula): Polyvinyl chloride resin (total 100 kg) K value 66-68 resin: 85 kg; K value 57-60 resin: 15 kg; Stabilization and acid inhibition system (3.00 kg in total) Calcium-zinc complex stabilizer: 1.60 kg; reactive phosphite: 0.35 kg; magnesium-aluminum-carbonate layered double hydroxide: 0.80 kg; imidazolium salt loaded mesoporous silica acid trapping agent: 0.25 kg; Foaming and nucleation (2.20 kg in total) Controlled release sodium bicarbonate-organic acid microcapsule: 0.90 kg; expandable polymer microsphere: 0.80 kg; flaky talc powder: 0.30 kg; organically modified montmorillonite: 0.20 kg; Near-surface reaction-adsorption transition layer components (3.00 kg in total, referred to as transition layer compound particles) Beta-cyclodextrin grafted aminosilica: 1.20 kg; zinc ion-exchanged 13X zeolite: 1.00 kg; eight-functional epoxide cage silsesquioxane (added in the form of a dispersion, calculated as solid): 0.35 kg; refined layered double hydroxide: 0.45 kg; Bulk buffering microporous adsorption (optional 0.50 kg) Mesoporous silica and light-colored activated carbon compound powder: 0.50 kg; Compatibility, toughening and low migration lubrication (14.00 kg in total) Acrylate processing aid: 1.20 kg; core-shell structure toughening agent: 7.00 kg; polymeric aliphatic dibasic acid ester plasticizer: 3.20 kg; epoxidized vegetable oil: 1.80 kg; polymeric ester wax (external lubricant): 0.40 kg; oxidized polyethylene wax (internal lubricant): 0.40 kg; It should be noted that the skin coating is coated online, and is separately prepared at a dry coating amount of 0.90 kg / m2, and is not included in the above solid weighing.

[0054] 2. Preparation of special intermediates 2.1. Beta-cyclodextrin grafted aminosilica (for transition layer compound particles) Target batch size: 2.0 kg of finished product Step A: Preparation of aminosilica In a solvent-resistant jacketed kettle, add 1.60 kg of silica microparticles (specific surface area ≥ 200 m2 / g), add 16 kg of anhydrous isopropanol to form a 10% (mass fraction) slurry, and start stirring (400-600 rpm).

[0055] Add 3-aminopropyltriethoxysilane 0.128 kg (8% by weight of silica), and slowly add deionized water 0.10 kg to make the system contain about 0.6% moisture to promote hydrolysis and condensation.

[0056] Maintain the temperature of the kettle at 70-80 degrees Celsius and reflux for 3 hours.

[0057] Filter and wash with isopropyl alcohol and deionized water (1:1 by volume) alternately until the conductivity of the filtrate is <50 microsiemens / centimeter.

[0058] Dry the filter cake under vacuum at 60-80 degrees Celsius for 8-12 hours, crush through a 120 mesh screen, and obtain about 1.65 kg of aminated silica.

[0059] Step B: Cyclodextrin activation and coupling grafting (succinylated-carbodiimide activation method) In a glass-lined reaction kettle, dissolve beta-cyclodextrin 0.70 kg in dimethylformamide 4.0 kg, and add succinic anhydride 0.21 kg under stirring, and react at room temperature to 50 degrees Celsius for 4-6 hours to prepare the succinylated beta-cyclodextrin intermediate.

[0060] Disperse the aminated silica obtained in Step A 1.50 kg in deionized water 7 kg, and adjust the pH to 5.5-6.5 (dilute hydrochloric acid or dilute sodium hydroxide solution) after ultrasonic treatment for 10 minutes.

[0061] Add 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide hydrochloride 0.15 kg and N-hydroxysuccinimide 0.09 kg to the dispersion under stirring, and then slowly add the succinylated beta-cyclodextrin solution of Step B-1 (the dimethylformamide can be replaced with water first to reduce organic residues), or, as a further washing sequence: after succinylation, the reaction solution is concentrated under reduced pressure to a solid content >60%, and then precipitated in batches into 10 times the volume of anhydrous diethyl ether / ethyl acetate, and the filter cake is washed with ethanol:water=1:1 until there is no dimethylformamide odor; and finally dried under vacuum at 40 degrees Celsius until the solvent residue is <0.1%.

[0062] Green alternative (dependent item): provide a water-ethanol-sodium bicarbonate buffer system direct succinylation route (requires 50-60 degrees Celsius, 6-8 hours, and the addition of 0.5-1.0% 4-dimethylaminopyridine as a catalyst) to avoid the use of dimethylformamide.

[0063] React at room temperature for 2-4 hours while maintaining the pH at 5.5-6.5.

[0064] Filter and wash with deionized water until the filtrate has no cyclodextrin reaction with iodine-starch test paper, and the weight loss at 105 degrees Celsius for 1 hour is <1.0%.

[0065] 60°C for 12 hours in vacuum, lightly crush through 200 mesh screen, about 2.0 kg of finished product.

[0066] Quality requirements: primary amine base density 1.2-1.6 mmol / g; cyclodextrin loading 0.3-0.5 mmol / g; average particle size 0.2-0.5 micron; organic solvent residue <0.1%.

[0067] 2.2, Zinc ion-exchange 13X zeolite (for transition layer compounded particles) Target batch size: 2.0 kg of finished product Add 1.80 kg of 13X sodium zeolite to 18 liters of 0.8 mol / L zinc acetate solution (liquid to solid ratio 10:1), control temperature at 80-90°C, stir for 3 hours.

[0068] Filter, repeat with equal volume of fresh zinc acetate solution for 2nd exchange for 2 hours.

[0069] Wash with deionized water until filtrate conductivity <200 microsiemens / cm.

[0070] Hot air dry at 120°C for 4-6 hours, optionally heat at 260-280°C for 1 hour to stabilize exchange sites.

[0071] Lightly crush through 325 mesh screen, about 2.0 kg of finished product.

[0072] Quality requirements: zinc exchange degree >60%; average particle size 1-3 micron; ignition loss <3%.

[0073] 2.3, Eight-functional epoxy cage silsesquioxane dispersion (for transition layer compounded particles) Target batch size: 0.7 kg of dispersion (solid content about 60%, equivalent to 0.42 kg of cage silsesquioxane) In a 2 liter beaker with stirring, add polymeric aliphatic dibasic acid ester plasticizer 0.28 kg, heat to 60-70°C.

[0074] Slowly add eight (glycidyloxypropyl) cage silsesquioxane powder 0.42 kg, shear disperse (1000-1500 rpm) for 30-45 minutes until no visible agglomeration.

[0075] Cool to room temperature, seal and store away from light. Quality requirements: dispersion solid content 58-62%; no significant sedimentation and caking at room temperature for 7 days; epoxy equivalent weight 500-800 g / eq.

[0076] 2.4, Controlled release sodium bicarbonate-organic acid microcapsule (for foaming) Target batch size: 2.0 kg of finished product Core material premix: In a blender, add sodium bicarbonate 1.05 kg and citric acid 0.85 kg (molar ratio about 1.3:1), dry mix for 10 minutes; add stearic acid 0.02 kg as hydrophobic wetting agent, mix for another 5 minutes.

[0077] Shell material preparation: Prepare shell material emulsion (ethyl cellulose and acrylic copolymer emulsion, mass ratio 2:1, total solid content 20%), add silane type surfactant 0.5-1.0% (relative to solid).

[0078] Fluidized bed spraying: Load the core material into the fluidized bed (bed temperature 40-45 degrees Celsius), spray the shell material emulsion at a speed of 0.4-0.6 ml / min, atomization pressure 0.15-0.20 MPa, control the outlet air temperature at 45-50 degrees Celsius, spray until the shell content is 20±3%.

[0079] Post-curing and sizing: After discharging, keep the temperature at 60 degrees Celsius for 2 hours, pass through an 80-mesh sieve, collect the 20-80 micron particle size fraction, and obtain about 2.0 kg. The quality requirements are: ignition temperature 160-170 degrees Celsius; weight loss at 105 degrees Celsius for 1 hour ≤3%.

[0080] 2.5, Silica sol-gel skin coating (for L1) Objective: Working solution for coating 500-1000 square meters Preparation of precursor sol (mass ratio, tetraethoxysilane = 1.00 as the basis): Tetraethoxysilane 1.00; 3-(methacryloyloxy)propyltrimethoxysilane 1.00; vinyltrimethoxysilane 0.50; n-octyltrimethoxysilane 0.10.

[0081] The solvent is anhydrous ethanol / deionized water with a volume ratio of 4:1, and a small amount of hydrochloric acid is added to adjust the pH to 2.5-3.5. Age at room temperature for 45 minutes.

[0082] Nanosilica dispersion: particle size 20-40 nm, surface modified with 3-(methacryloyloxy)propyltrimethoxysilane, solid content 20-30%.

[0083] Compounding and filtering: Mix the precursor sol and nanosilica dispersion at a mass ratio of 2:1, filter through a 100-200 mesh stainless steel filter, and let stand for 30 minutes to remove bubbles.

[0084] Working solution solid content: control at 20-25%, adjust the ethanol ratio according to the viscosity when spraying or spreading.

[0085] Safety: explosion-proof throughout, the body and waste liquid collection are unified according to the management of flammable and hazardous chemicals.

[0086] 3, Dry mixing and melt blending of main material 3.1. High speed dry mixing (target discharge temperature ≤ 115 °C) Order of addition and time (for this batch): Step 1 (60-90 seconds, 600-800 rpm): Add 100 kg of polyvinyl chloride resin, start stirring, and heat to 70-80 °C; Step 2 (90-120 seconds): Add calcium-zinc stabilizer 1.60 kg, reactive phosphite 0.35 kg, and epoxidized vegetable oil 1.80 kg in sequence, continue stirring to 85-90 °C; Step 3 (120-180 seconds): Add acrylate processing aid 1.20 kg and core-shell structure toughener 7.00 kg, and make sure the powder is fully coated; Step 4 (60-90 seconds): Add polymeric fatty acid ester 3.20 kg and lubricants (polymeric ester wax 0.40 kg, oxidized polyethylene wax 0.40 kg); Step 5 (60-90 seconds): Add controlled release microcapsules 0.90 kg, expandable microspheres 0.80 kg, flaky talc 0.30 kg, and organically modified montmorillonite 0.20 kg; Step 6 (60-90 seconds): Add layered double hydroxide 0.80 kg and imidazolium salt-loaded mesoporous silica acid-trapping agent 0.25 kg; Step 7 (60-90 seconds): Pre-add β-cyclodextrin grafted aminosilica 0.48 kg (40% of total) in transition layer complex particles, zinc-exchanged zeolite 0.40 kg (40% of total), and refined layered double hydroxide 0.18 kg (40% of total) for basic dispersion; Discharge and cooling: When the material temperature approaches 110-115 °C, discharge to a cooling stirring pot, cool to below 40 °C, and stand for 1-2 hours before use; Moisture and bulk density: dry mixed material contains ≤0.2% water; bulk density is stable (fluctuation ≤5% in drop test).

[0087] 4. Twin-screw melt blending-foaming-profile extrusion (including side-feeding directional enrichment) 4.1. Extruder parameters and temperature profile Screw length-diameter ratio 40-48:1; recommended arrangement: feeding section → compression section → mixing section → degassing section → metering section → side-feeding port → mixing section → vacuum degassing → metering section → head. Temperature zone setting (from feeding port to head): 150 / 160 / 165 / 170 / 170 / 165 °C; head 165 ± 5 °C. Main machine screw speed 45-60 rpm (tuned according to torque and melt pressure). First degassing port at atmospheric pressure, second degassing port connected to vacuum, vacuum degree ≥−0.08 MPa. Preheat barrel and die ≥30 minutes before extrusion.

[0088] 4.2, Main feeding and side feeding process Main feeding: The dry mixture obtained in Section 3 is continuously and uniformly added into the main feeder; the melt pressure and current are recorded after stabilization.

[0089] Side feeding and directional enrichment (forming a near-surface transition layer): At the side feeding port near the front of the metering section of the machine head, the remaining 60% of the transition layer compound particles are continuously added: β-cyclodextrin grafted aminosilica 0.72 kg; zinc ion-exchanged 13X zeolite 0.60 kg; refined layered double hydroxide 0.27 kg.

[0090] At the same time, an eight-functional epoxy cage-like silsesquioxane dispersion (0.35 kg of solid, about 0.58 kg of dispersion at 60% solid content) is added in liquid or paste form and injected near the side feeding port through a gear pump or injection valve.

[0091] The side feeding metering screw speed is set to 120-130% of the main machine screw speed to reduce excessive mixing of particles and promote their migration to the near-wall flow area. The average melt residence time in this section is 20-40 seconds, with moderate shear strength, ensuring that the particles are not completely kneaded, thereby forming a clear enrichment zone 10-30 microns from the surface. Vacuum exhaust and metering: open the vacuum exhaust port and maintain a pressure of−0.08 MPa or higher to remove trace amounts of water and volatile substances; the last metering section maintains stable pressure fluctuations (within ±0.5 MPa).

[0092] 4.3, Die, foaming and shaping Die temperature 165±5 degrees Celsius; the die gap matches the target profile size, with a shrinkage rate of 1.0-1.5% reserved for the first trial.

[0093] Foaming control: the expansion of microcapsules and polymer microspheres is adjusted by the barrel end temperature and melt pressure; if large bubbles or increased connectivity are observed, the machine head temperature is appropriately reduced by 3-5 degrees Celsius or the pulling speed is increased by 5-10%.

[0094] Vacuum sizing and cooling: the sizing water tank vacuum is−0.06 to−0.08 MPa; the water temperature is 15-20 degrees Celsius; the pulling speed and extrusion amount are matched to prevent skin tearing and orange peel on the surface.

[0095] Cutting and stacking: cut to the specified length to avoid melt marks caused by hot cutting; the profile is naturally cooled on the flat roller to <35 degrees Celsius before entering the next step of surface treatment.

[0096] 5, Online surface activation and skin coating (L1) coating and curing 5.1, Surface activation Using corona or plasma device, power density 40-60 watt-minute / square meter, distance from nozzle 3-5 millimeter, relative moving speed matching with pulling speed.

[0097] Time interval between activation and coating ≤2 minutes, to avoid surface energy drop.

[0098] 5.2, Coating Fill the prepared silicone working solution in Section 2.5 into a metering pump, and use comma doctor blade or gravure roll to coat uniformly. Target dry coating weight 0.90 gram / square meter, and calculate wet coating weight according to solid content 20-25% (usually 3.6-4.5 gram / square meter).

[0099] Adjust the doctor blade gap, screen roll line number and viscosity in linkage, to make dry film thickness 0.8-2.0 micrometer, preferably 1.2 micrometer. For areas that need strong adhesion with sealant, use masking tape to skip coating or switch polarity to enhance the formulation, and keep the adhesion window width 5-8 millimeter.

[0100] 5.3, Drying and Moisture Curing Immediately after coating, enter the hot air channel of 60-80 degrees Celsius for 30-90 seconds, and dry to the touch.

[0101] After exiting the oven, place in the environment of 23-30 degrees Celsius and relative humidity 50-70% for 48 hours, to complete the condensation and crosslinking of silicone network; when stacking, use dust-free film to isolate between profiles, to avoid mutual adhesion or indentation. As a further option, the residual alcohol content in the film within 1 hour after coating is ≤10% (TGA rapid determination); after 48 hours, the attenuation of the ethoxy residual peak (FTIR 1080-1100 cm⁻¹) is ≤30% of the initial value; if the ambient humidity is <45%, misted distilled water 1-3 g / m² is needed to promote condensation; provide UV-Sol-Gel fast curing alternative: under the condition of 1% photoinitiator, 200-400 mJ / cm² ultraviolet energy can reduce the moisture curing time to 4-6 hours.

[0102] 6, Curing, Inspection and Packaging Curing: avoid high temperature and direct blowing of strong wind within 48-72 hours after coating; it is recommended to stand in a clean room with relative humidity 50-70%.

[0103] Key appearance and structure inspection: visual and tactile: the surface should be continuous, without pinholes and visible flow marks; film thickness sampling: ellipsometry or white light interferometry, take one point every 10 meters, target 1.2±0.3 micrometer; near-surface enrichment verification: cross-section sampling, use microscopic infrared or energy spectrum mapping to confirm the signal enhancement of functional particles 10-30 micrometers deep. Moisture and cleanliness: control the moisture and dust on the surface of the profile, and wipe with a dust-free cloth before packaging.

[0104] Packaging: aluminum-plastic composite bag lining (with desiccant in each bundle), outer corrugated box or wrapping film; mark batch number, production date, coating formula number and precautions.

[0105] Storage and transportation: avoid co-transportation or co-storage with small molecule chemicals with strong volatility (such as diluents, solvent-based coatings, etc.); warehouse relative humidity 40-65%, temperature 5-35℃.

[0106] 7. Process control and abnormal adjustment Extrusion torque or melt pressure abnormally high: first reduce the head temperature and the second last zone temperature by 5℃, check if the expandable microspheres are expanded too early; if necessary, reduce the side feeding amount by 10%, and then restore after stabilization.

[0107] Cell size is too large or connected: appropriately increase the pulling speed by 5-10%, or reduce the controllable release microcapsule dosage by 0.05-0.10 phr; at the same time, increase the flaky talc by 0.05 phr.

[0108] Poor adhesion of skin coating: increase the surface activation energy to 60-70 W·min / m², or increase the proportion of 3-(methacryloyloxy)propyl trimethoxysilane in the working solution by 10-20%; if strong bonding area is required, ensure that the bonding window is free of coating residue.

[0109] Color is gray (commonly seen in high active carbon dosage): reduce the proportion of active carbon in the bulk buffer to 30-40% of the total amount, and replace it with mesoporous silica.

[0110] Initial odor is heavy: check if the dry mixing discharge temperature exceeds 115℃; confirm that the vacuum degree of vacuum exhaust is stable above−0.08 MPa; extend the product curing time to 72 hours.

[0111] I. Variable design of 5 groups of reference experimental examples Common premise: Polyvinyl chloride resin ratio, stabilizing system (calcium-zinc / phosphite / layered double hydroxide / imidazolium salt loaded mesoporous silica), compatible toughening lubricating system and most of the process parameters are the same as F-Base; Extrusion temperature zone: 150 / 160 / 165 / 170 / 170 / 165℃; head 165±5℃; vacuum exhaust≥−0.08 MPa; Target density 0.60±0.05 g / cm³; L2 directional enrichment target depth 10-30 μm (except R3 special instructions); The preparation and specifications of the special intermediates involved are the same as the previous scheme.

[0112] R1|Remove the skin anti-infiltration layer (L1) Change point: remove sol-gel skin coating (inactivation, no coating); rest as per F-Base, with L2 directional enrichment and bulk buffering (D3).

[0113] Objective: evaluate the interactive volatile organic amplification effect with only the anti-infiltration / diffusion barrier removed.

[0114] R2 | remove near-surface reaction-adsorption transition layer (D2) Change point: no β-cyclodextrin grafted aminosilica, zinc ion-exchanged zeolite, and octa-functional epoxide cage silsesquioxane added; skin coating L1 and bulk buffering D3 remain.

[0115] Objective: evaluate the performance with only the skin barrier and without in-situ immobilization.

[0116] R3 | remove directional enrichment (D2 changed to uniform dispersion) Change point: D2 added all at once in the main feed port and mixed thoroughly, no side feeding process used; uniform dispersion throughout the cross-section, no near-surface enrichment zone formed. L1 and D3 remain.

[0117] Objective: verify the contribution of position effect to the inhibition of interactive volatile organics.

[0118] R4 | replace the blowing system with conventional azodicarbonamide (ADC) Change point: C component changed to azodicarbonamide 0.60 phr + zinc oxide 0.20 phr (activation); remove controllable release sodium bicarbonate-organic acid microcapsules and inflatable microspheres; rest (L1, D2 directional enrichment, D3) remain.

[0119] Objective: compare the differences between low by-product blowing and conventional nitrogen-containing blowing in interactive scenarios.

[0120] R5 | remove bulk buffering adsorption (D3) Change point: no mesoporous silica / activated carbon compound powder added; L1 and D2 directional enrichment remain.

[0121] Objective: observe the effect of bulk capacity / buffering on thermal stimulation and long-term release.

[0122] II. Unified Test and Evaluation Method (Applicable to F-Base and R1-R5) Interactive Contact Working Conditions Contact Material A: Acid-cured silicone (releasing acetic acid); Contact Material B: Oxy-type neutral silicone (releasing ketoxime such as butanone oxime); Contact Material C: Single-component polyurethane blowing agent (releasing tertiary amine and other catalytic residues).

[0123] Samples were pressed face-to-face with the contact material, 10 cm2 effective contact area, 23°C, 50% relative humidity x 7 days; after removal, samples were allowed to rest for 24 hours before testing.

[0124] Thermal shock: some samples were subjected to thermal shock at 80°C x 8 hours after contact, and tested after 24 hours rest.

[0125] Emission testing (chamber method) A small environmental chamber was set up according to ISO 16000-9, and total volatile organic compounds (TVOC, pg / m3) were recorded; Data are expressed as the difference in TVOC (pg / m3) between the contacted sample and the uncontacted sample from the same batch.

[0126] Quantification of characteristic compounds Acidic silicone: acetic acid (pg / m3) was reported; Oxime-type silicone: methyl ethyl ketoxime (MEKO, pg / m3) was reported; Polyurethane blowing agent: total tertiary amine content (as triethylamine equivalent, pg / m3) was reported.

[0127] Thermal desorption (general for automotive interiors) VOC at 90°C (pg / mg) and Fog at 120°C (mg / mg) were recorded according to VDA 278, for material bulk comparison.

[0128] Aerosolization (glass method) Aerosol condensate mass (mg) was recorded according to DIN 75201 (Method B, mass method).

[0129] Surface and adhesion Water contact angle and surface energy (mN / m); Lap shear strength (MPa) with neutral silicone on the adhesion window (uncoated L1 area); End-face / surface TVOC gradient (%): TVOC was measured on the end-face and the side surface using a micro-chamber, and the difference between end-face and surface values was expressed as a percentage of the surface value.

[0130] Note: the following data are representative results, for patent example presentation and difference argumentation; if used for registration or supplier access, it is recommended to perform more than three replicates under the same conditions and to give the mean value and standard deviation.

[0131] III. Representative test data Table 1. List of samples and variables

[0132] Table 2. Emission and thermal shock results after contact with acidic silicone

[0133] * Thermal shock condition: 80℃ x 8h, then 24h recovery before measuring the incremental TVOC.

[0134]

[0135]

[0136] Table 5 General material properties and interface indicators (measured without contacting external materials)

[0137] IV. Results interpretation As can be seen from the comprehensive comparison, the benchmark sample (F-Base) forms a stable interception-fixation-buffering path for three types of contact systems (acidic silicone, oxime-type neutral silicone, and polyurethane blowing agent) under the three-level combination of the skin anti-infiltration layer L1 + near-surface reaction-adsorption layer L2 directional enrichment + bulk phase buffer D3.

[0138] After removing L1 from R1, the first barrier of low solubility and low diffusion coefficient on the surface is lost, and acetic acid, butanone oxime, and tertiary amine are more easily dissolved on the skin and penetrate along the bubble wall micropores, resulting in a significant increase in the incremental total volatile organic compounds and characteristic substances at room temperature, and the amplification is most obvious after thermal shock at 80°C. At the same time, the surface energy increases and the water contact angle decreases, causing the end-surface gradient to increase sharply, indicating that the diffusion channel changes from surface to bulk, and the secondary release is significantly amplified.

[0139] R2 retains L1 but removes L2, which shows that the initial increment is lower than R1 but still higher than the benchmark, indicating that physical barriers alone cannot inhibit the penetration and re-release of dissolved substances. The lack of β-cyclodextrin inclusion, strong adsorption of zinc-exchanged zeolite to amines, and structural fixation of epoxide cage silsesquioxane results in insufficient in-situ chemical locking ability, especially after thermal shock and back spray.

[0140] R3 changes L2 from directional enrichment to uniform dispersion, and the results show that the indicators are between R2 and the benchmark, clearly showing the position effect - when functional particles are concentrated in the enrichment zone 10-30 microns from the surface, they can capture and fix at the initial stage of molecular penetration, shortening the mass transfer path and reducing the effective diffusion coefficient. Uniform dispersion dilutes the near-surface active site density, reducing the interception efficiency.

[0141] After replacing the microcapsules + inflatable microspheres with azodicarbonamide and expanding, the thermal desorption and atomization indicators increase significantly, and the total amount of tertiary amine increases significantly when contacting polyurethane, reflecting the bulk source and mutual coupling caused by nitrogen-containing blowing by-products and their fragments. At the same time, the pores tend to be coarse and connected, further increasing the migration flux, making it difficult for the skin and transition layer to completely offset this amplification effect.

[0142] R5 without D3, the increment after 7 days of contact at room temperature is close to the baseline, but significantly higher than the long-term tail gas after thermal stimulation, indicating that the lack of bulk buffer will weaken the peak clipping and valley filling ability: foreign small molecules may still accumulate in the body after being intercepted by L1 and L2, and will be released in a concentrated manner when the temperature or pressure fluctuates.

[0143] In summary, the necessity and non-obviousness of the three-layer synergy are demonstrated: L1 is responsible for anti-infiltration and diffusion reduction, L2 is fixed in place through interlocking-coordination-reaction solidification, and D3 provides bulk capacity and long tail shaping; the lack of any layer will expose the short board under certain working conditions. The principles of surface energy window control, L2 directional enrichment process implementation, and low by-product foaming route should be adhered to in the design to obtain robust inhibition of multi-source interactive volatile organic compounds.

[0144] Those skilled in the art can realize that the units and algorithm steps of the examples described in combination with the embodiments disclosed herein can be realized in electronic hardware or a combination of computer software and electronic hardware. Whether the functions are realized in hardware or software depends on the specific application and design constraints of the technical solution. Professionals can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of the present application.

[0145] Those skilled in the art can clearly understand that, for the convenience and brevity of the description, the specific working process of the system, device and unit described above can refer to the corresponding process in the foregoing method embodiments, which will not be repeated here.

[0146] In several embodiments provided in the present application, it should be understood that the disclosed system, device and method can be realized by other ways. For example, the device embodiments described above are only schematic, for example, the division of the units is only a logical function division, and actual implementation can have another division manner, for example, multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. In addition, the coupling or direct coupling or communication connection between the units shown or discussed can be indirect coupling or communication connection through some interface, device or unit, and can be electrical, mechanical or other forms.

[0147] The units described as separate components can or can not be physically separated, and the components shown as units can or can not be physical units, i.e. they can be located in one place or distributed on multiple network units. Some or all of the units can be selected according to actual needs to achieve the purpose of the embodiment scheme.

[0148] The above merely provides the specific implementation of the present application, but the protection scope of the present application is not limited to this. Any person skilled in the art can easily think of the changes or replacements within the technical range disclosed by the present application, which should be covered in the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the protection scope of the claims.

Claims

1. A low-VOC environmentally friendly foamed PVC profile, characterized in that: include, The layers arranged from the outside to the inside are: L1, an anti-wetting skin layer; L2, a near-surface reactive adsorption transition layer; and L3, a core phase. L1 is a dense coating composed of an organic-inorganic silicon-oxygen network formed by sol-gel of 3(methacryloyloxy)propyltrimethoxysilane, vinyltrimethoxysilane, tetraethoxysilane and octyltrimethoxysilane, and combined with nano-sized silica with a particle size of 20–40 nm. It has a thickness of 0.8–2.0 μm, a surface energy of 24–28 mN / m, and does not contain fluorine-containing structures. L2 is located in a band-shaped region 10–30 μm from the surface, containing β-cyclodextrin-grafted aminated silica, zinc ion-exchange zeolite (13X or 5A, zinc exchange degree ≥60%), octafunctional epoxy cage-like silsesquioxane and refined layered double hydroxides. The volume fraction of L2 in this band is 2–3 times that of the bulk phase and the enrichment ratio is ≥2. L3 is a PVC foam core phase with a density of 0.55–0.65 g / cm³. The foaming system is a combination of controlled-release sodium bicarbonate organic acid composite microcapsules and expandable polymer microspheres. The PVC resin is composed of 80–90 parts of resin with a K value of 66–68 and 10–20 parts of resin with a K value of 57–60.

2. The low-VOC environmentally friendly foamed PVC profile according to claim 1, characterized in that: The working fluid for L1 coating has a solid content of 20–25% and a dry coating weight of 0.6–1.2 g / m². The precursor sol is composed of tetraethoxysilane: 3(methacryloyloxy)propyltrimethoxysilane: vinyltrimethoxysilane: n-octyltrimethoxysilane in a mass ratio of 1.0:1.0:0.5:0.10, and mixed with nano-silica with a particle size of 20–40 nm in a mass ratio of 2:

1.

3. The low-VOC environmentally friendly foamed PVC profile according to claim 2, characterized in that: The composition of the L2 near-surface reactive adsorption transition layer is as follows: 1.0–1.5 phr of β-cyclodextrin-grafted aminated silica, 0.8–1.2 phr of zinc ion-exchange zeolite, 0.25–0.45 phr of octafunctional epoxy cage-like silsesquioxane, and 0.3–0.6 phr of refined layered double hydroxide.

4. The low-VOC environmentally friendly foamed PVC profile according to claim 1, characterized in that: The enrichment of L2 was quantitatively determined by cross-sectional micro-infrared / energy dispersive spectroscopy / time-of-flight secondary ion mass spectrometry with a 5 μm step along the thickness direction, wherein the functional particle signal intensity in the band 10–30 μm from the surface was ≥2 times that of the bulk phase.

5. The low-VOC environmentally friendly foamed PVC profile according to claim 1, characterized in that: The L3 foaming system comprises controlled-release sodium bicarbonate organic acid composite microcapsules (0.7–1.2 phr, shell material is ethyl cellulose and acrylic copolymer, initial expansion temperature 165±5℃) and expandable polymer microspheres (0.6–1.0 phr, acrylonitrile-methyl methacrylate shell, initial expansion temperature 140–150℃), and contains flake talc (0.2–0.4 phr) and organically modified montmorillonite (0.15–0.30 phr).

6. A method for preparing low-VOC environmentally friendly foamed PVC profiles, characterized in that: include, A) Dry mix according to the formula and incorporate the controlled-release sodium bicarbonate organic acid composite microcapsules and expandable polymer microspheres; B) Twin-screw extrusion foaming molding, with temperature zones set at 150 / 160 / 165 / 170 / 170 / 165℃, die head at 165±5℃, and vacuum exhaust ≥−0.08MPa, yields foam core profiles with a density of 0.55–0.65g / cm³. C) Add 60% of the transition layer composite particles to the side feed port near the head of the machine and inject the eight-functional epoxy cage-like silsesquioxane dispersion through a gear pump, so that the β-cyclodextrin-grafted aminated silica and zinc ion exchange zeolite are enriched in the 10–30 μm zone from the surface, with an enrichment ratio ≥2. D) Activate the outer surface with corona or plasma at 40–60 W·min / m², coat with a sol composed of 3(methacryloyloxy)propyltrimethoxysilane, vinyltrimethoxysilane, tetraethoxysilane, n-octyltrimethoxysilane, and nano-silica, dry with hot air at 60–80°C for 30–90 seconds, and cure by standing at 23–30°C and 50–70% relative humidity for 48 hours to obtain an L1 skin with a thickness of 0.8–2.0 μm and a surface energy of 24–28 mN / m.

7. The method for preparing low-VOC environmentally friendly foamed PVC profiles according to claim 6, characterized in that: The twin-screw extruder is equipped with only two sets of 30° low-strength kneading blocks and conveying elements at the end. The specific energy of the end section is ≤0.08kWh / kg. The first exhaust port is at atmospheric pressure and the second exhaust port is at vacuum ≥−0.08MPa. The side-feed metering screw speed is 120–130% of the main unit speed, and the average melt residence time in the near-wall flow zone is 20–40 seconds.

8. The method for preparing low-VOC environmentally friendly foamed PVC profiles according to claim 6, characterized in that: L2 near-surface enrichment is achieved through micro-layer co-extrusion or annular melt injection: a two-channel micro-layer diverter is connected in series in front of the die to incorporate highly concentrated D2-containing material at a flow rate of 3–6% to form a 12–25 μm skin layer, or an annular injection slit of 0.3–0.5 mm is opened in the die transition section and injected at 0.8–1.2 kg / h to form an annular near-surface zone.

9. The method for preparing low-VOC environmentally friendly foamed PVC profiles according to claim 6, characterized in that: The interval between activation and coating should be ≤2 minutes; after coating, dry with hot air at 60–80℃ for 30–90 seconds, and then allow to stand for 48 hours at 23–30℃ and 50–70% relative humidity for moisture curing; or use a UV curing scheme: apply 200–400 mJ / cm² UV energy under 1% photoinitiator conditions and cure for 4–6 hours.

10. The method for preparing low-VOC environmentally friendly foamed PVC profiles according to claim 6, characterized in that: For the stop / overlap area where strong adhesion with sealant is required, leave a 5–8 mm uncoated area or use a polar-enhanced variant (add 0.05–0.10 parts by weight of 3-aminopropyltriethoxysilane and adjust vinyltrimethoxysilane to 0.3 parts by weight in the working fluid), the surface energy of the corresponding area is 30–32 mN / m, and the surface energy of the remaining exposed surfaces is 24–28 mN / m.

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