| HS Code | 580432 |
| Chemical Name | polyvinyl alcohol |
| Appearance | white to cream granular powder |
| Hydrolysis Mol Percent | 98.5-99.5 |
| Viscosity 4 Percent Solution 20c | 25 mPa·s (nominal) |
| Ph 4 Percent Solution | 5.0-7.0 |
| Ash Content Percent | 1.0 max |
| Volatile Matter Percent | 5.0 max |
| Solubility | soluble in water; requires heating for full dissolution |
| Specific Gravity | 1.27-1.31 |
| Melting Point C | 230-240 |
| Glass Transition Temperature C | 75-85 |
| Film Properties | tough, flexible, and transparent |
As an accredited ELVANOL T-25 factory, we enforce strict quality protocols—every batch undergoes rigorous testing to ensure consistent efficacy and safety standards.
| Packing | ELVANOL T-25 is supplied as free-flowing white granules in 25 kg multi-wall paper bags with a polyethylene liner. |
| Container Loading (20′ FCL) | ELVANOL T-25 packed in 20’ FCL, palletized bags, secured with dunnage, protected from moisture, heat, and contamination. |
| Shipping | ELVANOL T-25 (polyvinyl alcohol) ships as a non-hazardous dry powder in sealed bags or containers. Protect from moisture, humidity, and physical damage. Avoid extreme heat and open flames. No special dangerous-goods declaration required, but use clean, dry transport with adequate ventilation. |
| Storage | Store ELVANOL T-25 in tightly sealed original containers in a cool, dry, well-ventilated area. Protect from moisture, humidity, heat, and direct sunlight. Keep away from strong oxidizers and ignition sources. Ensure containers are labeled and intact, and follow good housekeeping practices to prevent dust accumulation. |
| Shelf Life | Shelf life is typically 2 years from manufacture when stored in original, unopened containers under dry, cool conditions. |
In alkaline fine paper furnishes carrying precipitated calcium carbonate filler loadings above 18 wt%, the size press film former must balance surface strength, porosity control, and toner adhesion without raising size bath viscosity beyond the operating window of a metering size press. ELVANOL T-25 is a fully hydrolyzed polyvinyl alcohol with a 4% aqueous solution viscosity of 3.0–3.7 mPa·s at 20°C and a hydrolysis degree of 99.0–99.8 mol%, which permits higher solids make-down in starch-containing surface size formulations while still forming a continuous oil and grease resistant film. In starch-based size press formulations, T-25 is incorporated at 0.5–2.0 wt% of the size bath solids or 2–5 parts per 100 parts of converted starch solids; in starch-free surface sizing, bath solids are commonly run at 2–6 wt% when T-25 is the dominant film former. The dried pick-up on the sheet is adjusted to 0.05–0.4 g/m² depending on grade, with higher pickups used on uncoated inkjet and laser printing grades where surface strength is limiting. Compliance for food-contact grades is assessed under 21 CFR 176.170 for aqueous and fatty foods and 21 CFR 176.180 for dry food, with water absorptiveness reported by ISO 535 or TAPPI T 441 Cobb methods. Terminal products include cut-size office paper, envelopes, folding carton stock, and direct thermal base paper.
Make-down for surface sizing is performed in a jacketed cooker with a high-shear disperser. ELVANOL T-25 is dispersed in cold water under agitation at 600–1200 rpm, then heated to 90–95°C and held for 45–60 min to complete dissolution before dilution to final solids. The solution is cooled to 55–65°C and delivered to the size press puddle or film transfer chamber. On metering size presses running at 600–1200 m/min, the low molecular weight of T-25 reduces shear-induced streaks and rod metering pressure compared with medium-viscosity PVOH grades. A process boundary exists at solution solids above 15 wt%, where surface skinning can occur during hold times longer than 90 min if the cooker is not blanketed; agitator speed is maintained at 20–30 rpm during storage. The pH of the final size bath is held between 7.0 and 8.5 to avoid starch acid hydrolysis and to minimize viscosity drift in the puddle. Addition of borate-based soluble starch crosslinkers is avoided because borate ions interact with the diol structure of fully hydrolyzed PVOH and create a steep viscosity increase that cannot be controlled on the run.
| Standard / Regulation | Test Method / Clause | Reported Parameter |
|---|---|---|
| 21 CFR 176.170 | Components for aqueous and fatty food contact | Food-contact extractives compliance |
| 21 CFR 176.180 | Components for dry food contact | Food-contact extractives compliance |
| ISO 535 | Cobb method, 60 s | Water absorptiveness, g/m² |
| TAPPI T 441 | Cobb test for sized paper and board | Water absorptiveness, g/m² |
The slasher sizing operation requires a film former that penetrates dense warp yarns without accumulating excessively on the yarn surface at the size box. ELVANOL T-25 is applied in size bath formulations at 6–10 wt% bath solids, with a dry polyvinyl alcohol add-on of 1.5–3.0 wt% of warp yarn mass; in starch-blended formulations it can replace 20–50% of the starch solids to raise weaving abrasion resistance while lowering biological oxygen demand in desize effluent. Compliance on finished fabric is screened against ZDHC MRSL v3.1 and OEKO-TEX Standard 100 limits for residual formaldehyde and APEO; the warp size itself is removed before finishing, so residual polyvinyl alcohol on greige fabric is controlled by Desizing Efficiency Index or by AATCC 81 pH after scouring. The terminal fabric types include woven cotton and polyester-cotton sheeting, twill workwear, and denim constructions where the size must survive high loom speeds and drop wire abrasion.
At the slasher, T-25 is pre-dissolved at 10–12 wt% solids in a jet cooker at 85–95°C, then held in the size box at 75–85°C. A two-box slasher with high-pressure squeeze rolls is used to control wet pick-up at 60–70%; the low solution viscosity of T-25 improves penetration into the yarn core and reduces size box viscosity drift during long creel changes. Drying is carried out on 9-zone cylinder dryers with can temperatures stepped from 120°C to 150°C, and warp moisture is conditioned to 8–12% before weaving. The main process conflict is that the low molecular weight of T-25 produces lower film tensile strength than medium-viscosity fully hydrolyzed grades; for high-abrasion yarns or filament warps, a blend with a higher molecular weight PVOH is required. Borate-based processing aids are excluded because they react with the fully hydrolyzed polyvinyl alcohol backbone and generate uncontrolled viscosity peaks in the size box. Size bath pH is maintained at 6.5–8.0 to prevent hydrolysis of starch co-binders and to reduce size liquor discolouration on heated cans.
When vinyl acetate is polymerized in a seeded semi-batch reactor, the protective colloid governs particle size distribution, shear stability, and water resistance of the finished dispersion. ELVANOL T-25 is charged at 2–6 wt% based on total monomer mass, pre-dissolved in deionized water at 10–15 wt% solids and 90–95°C before being cooled to reactor temperature. In polyvinyl acetate homopolymer and vinyl acetate-ethylene copolymer dispersions, this fully hydrolyzed grade is selected when the dried adhesive film must retain bond strength under high humidity or wet conditions. The reactor is a jacketed stainless steel vessel with an anchor impeller at 100–200 rpm; the monomer feed is metered over 3–5 h while the redox initiator maintains reaction temperature at 60–75°C under a nitrogen purge. The final dispersion pH is adjusted to 4.5–5.5 after monomer stripping, and viscosity is reported by ISO 2555 Brookfield method. Terminal products include EN 204 D3/D4 wood adhesives, paper laminating adhesives, and packaging adhesives where FDA 21 CFR 175.105 may apply to indirect food contact.
The low molecular weight of T-25 produces lower solution viscosity at the same protective colloid solids than medium-viscosity fully hydrolyzed grades, allowing a higher colloid loading before the dispersion viscosity exceeds the 10,000 mPa·s upper limit of many transfer pumps. A known operational boundary is the lower electrolyte tolerance of fully hydrolyzed PVOH compared with partially hydrolyzed grades; polyvalent salts and cationic coagulants should be evaluated at pilot scale because they can induce visible coagulum on the reactor wall and filter screens. Batch-to-batch variation in the 4% solution viscosity of T-25, nominally 3.0–3.7 mPa·s, shifts final dispersion viscosity within ±5–10% when the colloid is near the upper addition level. Residual monomer is reduced to below 0.1 wt% by vacuum stripping before pH adjustment; the dispersion is then cooled and filtered through a 100–150 µm screen. If amine-based coalescing agents are added during formulation, compatibility with the fully hydrolyzed protective colloid should be confirmed because pH excursions above 8.0 can destabilize the dispersion during storage.
Mechanically, the binding contribution of a polyvinyl alcohol temporary binder in pressed technical ceramics arises from polymer bridges between spray-dried granules, and this contribution drops as molecular weight decreases. ELVANOL T-25 is therefore used in ceramic slurries at 1–5 wt% based on dry ceramic powder, with typical alumina formulations at 1.5–2.5 wt%, where its 3.0–3.7 mPa·s solution viscosity permits 40–60 wt% slurry solids without exceeding the pumpability limit of the spray dryer feed. Slurry preparation is carried out in a high-shear mixer; the binder is added as a 10 wt% aqueous solution after the ceramic powder and dispersant have been dispersed, and the slurry is then spray-dried at inlet temperatures of 180–220°C and outlet temperatures of 80–110°C. The spray-dried granules are uniaxially pressed at 80–150 MPa, and green machining may be performed before binder burnout. Terminal product types include alumina substrates, porous catalyst supports, and structural technical ceramic components. Binder burnout is validated by thermogravimetric analysis according to ISO 11358-1, and ash residue is checked by combustion at 600°C.
The critical process conflict is the inverse relationship between spray-drying pumpability and green strength: the low molecular weight of T-25 lowers slurry viscosity but produces lower green strength than a medium-viscosity PVOH at the same addition level. When green machining causes edge chipping or when pressed parts crack during demolding, the binder level can be increased to 3–5 wt%, but the burnout heating rate must then be held below 2°C/min to 600°C to avoid carbon residue. Above 5 wt% binder, organic burnout in thick sections can generate internal pressure and delamination, especially in parts thicker than 10 mm. The operational boundary is the moisture sensitivity of the spray-dried granules: at ambient relative humidity above 60%, granule strength changes and pressing defects increase unless the press room is conditioned to 40–50% RH. Because published data for T-25 in specific ceramic matrices is limited, binder burnout profiles are confirmed by differential thermal analysis for each ceramic grade before production.
Dry-mix cementitious formulations for tile adhesives, skim coats, and repair mortars use low-viscosity polyvinyl alcohol to increase water retention and improve wet adhesion without excessive air entrainment. ELVANOL T-25 is dosed at 0.2–1.5 wt% by mass of cementitious solids, with standard ceramic tile adhesive formulations typically in the 0.3–0.8 wt% range. The dry blend is produced in a horizontal ribbon mixer with a 5–10 min mixing cycle; T-25 is added as a dry powder after the fine fillers and before the cellulose ether to avoid segregation. The mixed mortar is prepared on site with 20–25 wt% water, mixed with a high-shear paddle for 60–120 s, rested for 5 min, and remixed before notched-trowel application. Terminal product types include EN 12004-1:2017 Class C2 ceramic tile adhesives, EN 1504-3 structural and non-structural repair mortars, and gypsum or cement-based skim coats. Performance is validated by tensile adhesion pull-off tests under EN 12004-1 after standard water immersion, heat ageing, and freeze-thaw cycles.
The process limitation with PVOH in cementitious systems is hydration retardation at elevated addition levels; above 1.5 wt% on cement mass, the polymer can block early hydration products and reduce 28-day compressive strength enough to move a formulation outside the declared strength class. At the recommended 0.2–0.8 wt% window, the low molecular weight of T-25 dissolves rapidly in the mix water without generating the lumping observed with high-viscosity grades, but air entrapment should be checked because PVOH stabilizes foam under high-shear mixing. A defoamer may be added when the air content exceeds 3% after mixing. Published interlaboratory data for T-25 within EN 12004-1 adhesive matrices is limited; therefore the addition ratio is verified against open time, wet scrub resistance, and water retention before specification. The dry mix must be stored in moisture-proof packaging because T-25 absorbs atmospheric water above 70% RH, leading to caking in silos and loss of free-flowing segregation resistance.
Where closed-mold composite operations require a sacrificial barrier that can be removed with water after cure, ELVANOL T-25 is prepared as an aqueous release film at 2–10 wt% solution solids, with typical spray dilutions of 4–6 wt% to achieve a dry film thickness of 5–20 µm. The solution is made down at 90°C and cooled to 20–30°C before application; at 25°C the low solution viscosity permits atomization through airless spray equipment at fluid pressures of 0.7–1.2 bar. The mold surface is cleaned, heated to 60–80°C, sprayed in overlapping passes, and dried with forced air before lay-up. The resulting PVOH film acts as a sacrificial barrier that prevents epoxy, vinyl ester, or phenolic resin from wetting the tool surface. Terminal products include composite laminates, wind blade shells, and automotive moldings. Compliance is assessed under REACH registration and the absence of substances of very high concern above 0.1% w/w, with RoHS Directive 2011/65/EU applicable only when the final composite enters electrical and electronic equipment streams.
The main operational boundary is the water solubility that provides the release function: ambient relative humidity above 70% plasticizes the film and creates tack, while premature contact with water or water-based resin systems dissolves the barrier before cure. Spray booths are therefore conditioned to 40–60% RH and 20–25°C, and wet lay-up with waterborne resins is unsuitable unless a separate barrier coat is applied. Film thickness above 20 µm can leave deposits on textured mold surfaces after demolding, while thickness below 5 µm can fail by pinholing under vacuum bag consolidation. Because the T-25 grade is fully hydrolyzed, the dried film is less sensitive to cold water re-dissolution than partially hydrolyzed PVOH film, but re-dissolution speed is still high enough that demolded parts can be washed with warm water to remove residual film.
Competitive ELVANOL T-25 prices that fit your budget—flexible terms and customized quotes for every order.
For samples, pricing, or more information, please contact us at +8615380400285 or mail to sales2@liwei-chem.com.
We will respond to you as soon as possible.
Tel: +8615380400285
Email: sales2@liwei-chem.com
Flexible payment, competitive price, premium service - Inquire now!
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.
