| Código SH | 580432 |
| Nome Químico | álcool polivinílico |
| Aparência | Pó granulado branco a creme |
| Hidrólise Mol | 98.5-99.5 |
| Viscosidade Solução 4 Por Cento 20 C | 25 mPa · s (nominal) |
| Solução De Ph 4 | 5,0-7,0 |
| Porcentagem De Conteúdo De Cinzas | 1,0 máximo |
| Porcentagem De Matéria Volátil | 5,0 no máximo |
| Solubilidade | Solúvel em água; requer aquecimento para dissolução total |
| Gravidade Específica | 1.27-1.31 |
| Ponto De Fusão C | 230-240 |
| Temperatura De Transição Vítrea C | 75-85 |
| Propriedades Do Filme | Resistente, flexível e transparente |
Como uma fábrica acreditada ELVANOL T-25, aplicamos protocolos de qualidade rigorosos - cada lote é submetido a testes rigorosos para garantir padrões de eficácia e segurança consistentes.
| Embalagem | ELVANOL T-25 é fornecido como grânulos brancos de fluxo livre em sacos de papel de parede múltipla de 25 kg com um revestimento de polietileno. |
| Carga de contêiner (20' FCL) | ELVANOL T-25 embalado em 20 embalagens FCL, sacos paletizados, protegidos com esterilização, protegidos contra umidade, calor e contaminação. |
| Envio | ELVANOL T-25 (álcool polivinílico) é enviado como um pó seco não perigoso em sacos ou recipientes selados. Proteja da umidade, umidade e danos físicos. Evite calor extremo e chamas abertas. Nenhuma declaração especial de mercadorias perigosas é necessária, mas use transporte limpo e seco com ventilação adequada. |
| Armazenamento | Armazene ELVANOL T-25 em recipientes originais hermeticamente fechados em uma área fria, seca e bem ventilada. Proteja da umidade, umidade, calor e luz solar direta. Mantenha longe de oxidantes fortes e fontes de ignição. Certifique-se de que os recipientes estejam rotulados e intactos e siga boas práticas de limpeza para evitar o acúmulo de poeira. |
| Prazo de validade | A vida útil é tipicamente de 2 anos a partir da fabricação quando armazenado em recipientes originais fechados em condições secas e frias. |
Em móveis de papel fino alcalino que carregam cargas de enchimento de carbonato de cálcio precipitado acima de 18% em peso, o formador de filme de prensa de tamanho deve equilibrar a força da superfície, o controle da porosidade e a adesão do tóner sem aumentar a viscosidade do banho de tamanho além da janela de operação de uma prensa de tamanho de medição. ELVANOL T-25 é um álcool polivinil totalmente hidrolizado com uma viscosidade de solução aquosa de 4% de 3,0–3,7 mPa·s a 20°C e um grau de hidrólise de 99,0–99,8 mol%, o que permite a maior descomposição de sólidos em formulações de tamanho superficial contendo amido enquanto ainda forma um filme contínuo resistente ao óleo e à gordura. Em formulações de prensa de tamanho à base de amido, T-25 é incorporado em 0,5-2,0% em peso dos sólidos de banho de tamanho ou 2-5 partes por 100 partes de sólidos de amido convertidos; no dimensionamento superficial sem amido, os sólidos de banho são geralmente executados em 2–6% em peso quando T-25 é o formador de filme dominante. A captação seca na folha é ajustada para 0,05-0,4 g/m² dependendo da qualidade, com captações mais altas usadas em grades de impressão a jato de tinta e a laser não revestidos onde a resistência da superfície é limitante. A conformidade para os graus de contato com alimentos é avaliada de acordo com o 21 CFR 176.170 para alimentos aquosos e gordurosos e o 21 CFR 176.180 para alimentos secos, com absortividade de água relatada pelos métodos ISO 535 ou TAPPI T 441 Cobb. Os produtos terminais incluem papel de escritório de tamanho cortado, envelopes, estoque de caixa dobrável e papel de base térmica direta.
Preços competitivos ELVANOL T-25 que se encaixam no seu orçamento - termos flexíveis e orçamentos personalizados para cada pedido.
Para amostras, preços ou mais informações, entre em contato conosco em +8615380400285 Ou envie para sales2@liwei-chem.com.
Responderemos a você o mais rápido possível.
Telefone: +8615380400285
E-mail: sales2@liwei-chem.com
Pagamento flexível, preço competitivo, serviço premium - Consulte-nos agora!
ELVANOL T-25 is a partially hydrolysed polyvinyl alcohol resin supplied by Kuraray Co., Ltd. The grade is defined by a 4 % aqueous solution viscosity of 25–30 mPa·s at 20 °C, a degree of hydrolysis of 87–89 mol%, and a lot-release envelope that commonly includes pH 4.5–6.5, ash not exceeding 0.5 %, and volatile matter not exceeding 5.0 % when tested in accordance with JIS K 6726. ELVANOL T-25 is used as a protective colloid in vinyl acetate and acrylate emulsion polymerization, as a size press binder in paper and paperboard surface treatment, and as the base polymer in water-borne adhesive and textile warp-sizing formulations. Compared with fully hydrolysed polyvinyl alcohol grades of similar aqueous viscosity, the residual acetate content of ELVANOL T-25 suppresses crystallinity and permits cold-water dissolution below 40 °C, but it also lowers the water resistance, tensile modulus, and barrier performance of the dried polymer film. The selection of ELVANOL T-25 therefore requires a process-specific balance between low-temperature solubility and final film performance.
| Parameter | Typical range or limit | Test basis |
|---|---|---|
| 4 % aqueous solution viscosity | 25–30 mPa·s | 20 °C, capillary viscometry |
| Degree of hydrolysis | 87–89 mol% | saponification method |
| pH | 4.5–6.5 | 4 % aqueous solution |
| Ash content | ≤0.5 % | ignition residue |
| Volatile matter | ≤5.0 % | drying loss |
Make-down of ELVANOL T-25 begins with dispersion of granules into cold water under agitation to prevent lump formation, followed by heating to 60–70 °C for 30–45 min. High-shear rotor-stator or eductor powder injection systems are used at production scale; low-shear tanks without baffles can leave undissolved gel aggregates if the powder is charged too quickly. The partially hydrolysed grade dissolves at lower temperature than fully hydrolysed types, but a final temperature below 60 °C can leave microgel particles that later deposit on coating or casting equipment. Filtration through 60–100 mesh stainless steel screens is recommended before transfer. Storage of concentrated solutions above 12 % solids at ambient temperature can promote viscosity drift and, in non-bactericidal systems, microbial growth; closed stainless steel tanks with cooled jackets are therefore preferred for hold times beyond 8 h.
During the semi-batch emulsion polymerization of vinyl acetate or vinyl acetate-ethylene copolymers, ELVANOL T-25 is typically charged as a 4–6 wt% aqueous solution relative to total monomer mass. The 87–89 mol% hydrolysis degree provides an amphiphilic chain architecture that lowers interfacial tension and stabilizes polymer particles through both steric and grafted-chain mechanisms. Polymerization is commonly initiated with potassium persulfate at 70–75 °C, while monomer is metered over 3–5 h. At this temperature window, the rate of graft reaction between propagating poly(vinyl acetate) radicals and the PVA backbone remains controlled; temperatures above 80 °C accelerate side reactions that increase gel fraction and can cause reactor wall fouling. Production-scale jacketed reactors equipped with pitched-blade impellers at tip speeds of 1.5–2.5 m/s are used, but excessive agitator speed can generate foam that destabilizes the latex. The resulting particle size distribution for a homopolymer dispersion is typically in the 1–3 µm D50 range, while blends with a low-viscosity fully hydrolysed grade shift nucleation toward a finer distribution. Batch-to-batch shifts of ±1 mol% in the degree of hydrolysis are a known sensitivity in this application, and published data for continuous-loop reactor performance with ELVANOL T-25 is limited.
Control of dissolved oxygen is critical because PVA can undergo oxidative chain scission in the presence of persulfate and air; nitrogen sparging at 0.1–0.3 L/min/kg reaction mass is typical before initiation. Defoamer addition is often required because partially hydrolysed PVA stabilizes foam during monomer feeding; silicone-based defoamers at 50–200 ppm may be used, but excessive defoamer can create fisheyes in the final latex film. The reaction is terminated by adding a redox pair such as sodium metabisulfite and tert-butyl hydroperoxide at 0.05–0.10 % of monomer mass, after which residual vinyl acetate is stripped at 50–60 °C under reduced pressure. Final latex viscosity is adjusted by dilution or by blending with a low-viscosity PVA grade to meet a target of 2,000–5,000 mPa·s at 25 °C using ISO 2555 Brookfield measurements.
In puddle size press operations on fine paper and linerboard, ELVANOL T-25 is typically applied as a 4–8 % aqueous solution, either alone or blended with oxidized starch at a starch-to-PVA dry mass ratio between 90:10 and 70:30. Size press roll temperature is maintained at 60–70 °C; however, because the grade is partially hydrolysed, the make-down stage can begin with cold process water below 40 °C, reducing steam demand before the run tank. Dry pick-up on the sheet is generally controlled in the 1.5–3.0 g/m² range. Surface sizing response is quantified by the ISO 535 Cobb method at 60 s contact time; the addition of ELVANOL T-25 reduces Cobb values mainly by forming a continuous film that blocks liquid penetration. The extent of Cobb reduction is furnish-dependent and should be established by trial; published data for this specific configuration is limited. At addition levels above 5 % in the size press bath, viscosity rise can destabilize film splitting at high machine speeds, and the recommended control point is below 50 mPa·s at 60 °C.
Borate complexation with ELVANOL T-25 is used to generate shear-thinning, high-green-tack adhesive rheology for paper tube winding and carton sealing. A typical base mix contains 12–15 % ELVANOL T-25 solids, and borax decahydrate is added at 0.5–2.0 % of PVA dry mass. The pH of the borated adhesive rises to 8.5–9.2; gelation is rapid above 2.0 % borax and can produce irreversible syneresis if local concentration spikes are not dispersed. Low-shear paddle mixers operating at 30–60 rpm are preferred, and borax must be introduced as a dilute aqueous stream below the liquid surface. The resulting adhesive is measured with a Brookfield viscometer at 20 °C using spindles 3–6 at 20 rpm. Because borate crosslinks are reversible, the tack range remains open longer than with irreversible thermosetting systems, but the wet bond strength of borated T-25 films is lower than that of adhesives compounded with fully hydrolysed polyvinyl alcohol and blocked isocyanate crosslinkers. Adhesion to coated board is commonly measured by T-peel under ASTM D1876-08; published data for ELVANOL T-25 in this specific configuration is limited. Borax should not be combined with low-pH additives that would hydrolyse acetate groups during storage.
Textile warp sizing lines running at 60–80 m/min impose a narrow window for film formation, elasticity, and ease of desizing. ELVANOL T-25 is prepared at 8–12 % solids in the size cooker and applied from a size box held at 50–60 °C. Dry add-on is maintained between 8 % and 14 % on yarn mass for spun cotton or polyester-cotton blends. The partially hydrolysed grade gives a softer film than fully hydrolysed polyvinyl alcohol at equivalent add-on, which reduces brittleness at rapier picking points but also lowers resistance to high-humidity weaving rooms. Hairiness control is evaluated on a Zweigle hairiness tester according to in-house mill protocols; published values for ELVANOL T-25 on compact-spun yarns are limited. Desizing can be conducted in cold water below 30 °C, which is a significant process difference from fully hydrolysed grades that require 80 °C or above for size removal. However, cold-water solubility also means that size film re-moistening in humid weaving environments can increase warp sticking if the sizing formula contains hygroscopic plasticizers.
When ELVANOL T-25 is solution-cast from an 8–12 wt% aqueous dope, the dried film retains enough amorphous structure to dissolve in water at 20 °C within minutes, depending on plasticizer content. Glycerol is typically added at 10–20 phr to reduce embrittlement, but it increases equilibrium moisture uptake and reduces the barrier properties that a fully hydrolysed grade would provide. Film mechanical properties measured under ASTM D882-18 show formulation-dependent tensile strength; published data for unplasticized ELVANOL T-25 film is limited, and the useful comparison is therefore process-based rather than absolute. In applications where the film must remain intact under aqueous contact, ELVANOL T-25 is unsuitable unless a crosslinker such as glyoxal or a melamine-formaldehyde resin is added, but these additives can reduce cold-water solubility and raise formaldehyde release considerations under ISO 14184-1. Drying air temperature in tunnel ovens is maintained at 80–110 °C; temperatures above 120 °C can cause bubble defects as the surface skins over before internal water escapes. For high-clarity cast film, the dope must be filtered through 10–20 µm absolute-rated filters to remove undissolved gel particles.
In paper and paperboard food-contact adhesives, polyvinyl alcohol may be evaluated under FDA 21 CFR 175.105 and 21 CFR 176.170 for indirect contact, provided the formulated end-use meets the stated extraction and use limitations. ELVANOL T-25 is a trade name and is not by itself an approved article; converters must verify that the final adhesive or coating complies with the applicable migration limits and that the grade meets residual monomer and impurity specifications. For European Union applications, compliance may be assessed under food-contact plastics regulations including Regulation (EU) 10/2011 where polyvinyl alcohol is used as an additive or polymer in the final film. The REACH registration status of the grade should be confirmed with the supplier for industrial use outside the United States. Environmental release data for polyvinyl alcohol indicates ready biodegradability in adapted wastewater treatment, but specific degradation rates for ELVANOL T-25 under cold-water conditions are not readily available.
Ceramic green-tape casting using partially hydrolysed polyvinyl alcohol binds alumina or barium titanate powders through a burnout cycle in which organic matter must be removed before sintering. ELVANOL T-25 is dissolved at 8–12 % solids in water, then blended with ceramic powder and plasticizers such as poly(ethylene glycol) at 2–5 wt% of solids. The low ash limit of 0.5 % is a critical control point in ceramic dielectrics, where residual sodium or chloride affects dielectric loss. Thermogravimetric analysis at 10 °C/min in air is used to confirm clean burnout; complete decomposition is typically observed between 350 °C and 450 °C, but published burn-out profiles for ELVANOL T-25 in specific tape formulations are limited. Slot-die coating head gaps are set at 0.5–1.5 mm, and wet tape is dried at 60–80 °C to avoid binder migration. Compared with fully hydrolysed polyvinyl alcohol, the partially hydrolysed grade provides lower green strength after drying but easier cold-water cleanup of coating equipment. This trade-off is acceptable only when downstream handling does not require high flexural strength before sintering.
