Step-by-Step Process for Grade Matching in Textile Chemistry

Grade matching in textile chemistry requires more than comparing product names or viscosity values. This guide explains how to define the application, standardize testing, evaluate samples and verify an approved grade before bulk purchasing.

Grade matching is a common requirement when a textile factory changes suppliers, qualifies a backup source, develops a new formulation or attempts to replace an existing printing chemical. However, two products with similar names or specification ranges may not behave the same way in preparation, storage, printing, fixation or washing.

For technical buyers, the objective is not to find a product that appears identical on paper. The objective is to identify a candidate grade that can meet the factory’s critical process and final-quality requirements under controlled and repeatable test conditions.

This process is particularly important for textile printing thickeners and printing paste materials such as CMC, CMS, sodium alginate, compound thickeners and digital printing paste. The same principles can also be applied to other textile auxiliaries when the test criteria are adjusted to the intended application.

What Grade Matching Means in Textile Chemistry

Grade matching is a structured comparison between an approved reference product and one or more candidate grades. The comparison should cover the complete application rather than one isolated laboratory value.

For a textile printing thickener, this may include powder dispersion, hydration, viscosity, rheology, filtration, paste stability, screen passage, print definition, fixation, wash-off and final fabric handle. Commercial documentation and batch consistency must also be considered before the candidate is approved.

Grade matching is not the same as product identification

Product names such as CMC, CMS or sodium alginate identify a chemical family, but they do not define a complete commercial grade. Products in the same family can have different viscosity ranges, substitution levels, particle sizes, moisture limits, hydration behavior and application specifications.

A supplier should therefore avoid describing a candidate as a direct equivalent before application testing. A more reliable description is that the product is a proposed matching grade for controlled evaluation.

What a successful match should achieve

• Meet the defined critical technical requirements
• Remain compatible with the actual formulation and process water
• Produce an acceptable result on the intended fabric
• Remain practical for mixing, storage and production handling
• Provide suitable technical and batch documentation
• Demonstrate acceptable consistency from sample to commercial supply

When Is Grade Matching Required?

Grade matching may be initiated for technical, supply-chain or commercial reasons. Defining the reason at the beginning helps determine which acceptance criteria should receive the highest priority.

• Replacing a discontinued or unavailable textile chemical
• Sélection d'un deuxième fournisseur pour assurer la continuité de l'approvisionnement
• Reducing dependence on a single imported grade
• Changing the fabric, dye, pigment, ink or printing process
• Moving from laboratory development to production-scale printing
• Addressing slow hydration, viscosity drift or filtration problems
• Improving screen passage, outline definition or wash-off
• Comparing cost-in-use rather than price per kilogram
• Developing a custom printing paste or compound thickener

A single matching project should normally focus on one defined application. Reactive printing on cotton, pigment printing on cotton and digital pretreatment for cotton may use the same fabric but represent different chemical and process requirements.

Step 1: Define the Matching Objective

The first step is to define what the word “matched” means for the project. The objective may be equivalent production performance, an approved backup grade, improved filtration, easier preparation or a lower total cost in use.

Avoid starting with a general request for a product that is “the same or better in every way.” A useful project has measurable requirements and a clear approval decision.

Record the complete application

• Composition du tissu ou des fibres, y compris les proportions des mélanges
• Système à base de colorant, de pigment ou d'encre
• Printing method: flat screen, rotary screen, coating or digital route
• Machine type and normal operating conditions
• Fixation, drying and post-treatment process
• Current dosage and paste-preparation procedure
• Required print definition, penetration and fabric handle
• Main production problem to be solved

Separate critical requirements from preferences

Critical requirements are conditions that can stop production or make the finished fabric unacceptable. Examples may include severe screen blockage, unstable paste, incompatible dye behavior or unacceptable wash-off.

Noncritical preferences may include a minor difference in powder color, packaging format or preparation time. Separating these two groups makes the evaluation more consistent.

Step 2: Build a Reference Benchmark

The current approved product should be treated as the control. Before introducing a candidate, record how the reference product is prepared, tested and used in normal production.

Testing a candidate without a reference makes it difficult to determine whether a result was caused by the new chemical or by normal variation in fabric, water, dye, equipment or laboratory preparation.

Information to collect from the current product

• Current product name and permanent grade code
• Technical Data Sheet and Safety Data Sheet
• Representative physical sample with batch information
• Current viscosity specification and complete test method
• Powder appearance, particle size and hydration behavior
• Current dosage and full preparation procedure
• Temps de prise normal de la pâte avant l'impression
• Known production strengths and limitations

Confirm that the reference sample is representative

An opened, humid, contaminated or outdated sample may no longer represent the product used in normal production. Where possible, record the batch number, opening date and storage history.

The approved production product should remain the main benchmark. A damaged retained sample can send the matching project in the wrong direction.

Step 3: Select the Correct Chemical Route

Before choosing an exact grade, determine which product family should be evaluated. Selecting the correct chemistry route is more important than finding a similar viscosity within an unsuitable product family.

Sodium alginate route

Alginate de sodium is commonly evaluated for reactive dye printing systems where paste rheology, print definition and wash-off behavior need to be considered together.

Final suitability still depends on fabric, dye selection, auxiliaries, preparation, fixation and washing conditions. A sodium alginate grade should therefore be confirmed in the customer’s actual formulation.

CMC route

Carboxyméthylcellulose (CMC) is available in different viscosity and substitution ranges and may be evaluated for selected textile printing, sizing and formulation applications.

Buyers should confirm viscosity method, degree of substitution where relevant, solution behavior, compatibility and the intended dye or pigment system.

CMS route

Amidon carboxyméthylique (CMS) may be evaluated in selected printing and textile formulations where paste body, application performance and cost-in-use are part of the matching objective.

It should not be treated as a universal one-to-one replacement for another thickener family. Dosage and final performance need to be established by controlled testing.

Compound and digital printing paste routes

Compound thickeners may combine different material routes to achieve a specific balance of hydration, rheology, filtration and cost. The exact composition and recommended use should be reviewed through the supplier’s technical information and application trial.

For inkjet pretreatment and digital textile printing, evaluate a dedicated pâte d'impression numérique according to the ink system, fabric, filtration requirement, coating or padding method and final printing result.

Step 4: Standardize the Test Method

Viscosity values are meaningful only when the measurement conditions are known. Results obtained at different concentrations, temperatures, hydration times or instrument settings should not be treated as directly equivalent.

Record the complete viscosity method

• Sample concentration and preparation basis
• Source d'eau et température de l'eau
• Mixing equipment, mixing speed and mixing time
• Hydration and resting time before measurement
• Température de mesure
• Instrument model or measurement principle
• Spindle, rotor or geometry used
• Rotational speed or shear condition
• Reported unit and reading time

When the supplier and buyer use different viscosity methods, record both methods and retest the reference and candidate with one common internal procedure. Do not convert values by assumption unless an appropriate validated correlation is available.

Control preparation variables

Use the same batch of water, identical containers and the same mixing sequence for all samples. Keep sample temperature and resting time as consistent as practical.

Any deviation should be recorded. Small changes in preparation can create an apparent product difference that is not caused by the grade itself.

Step 5: Screen Candidate Samples

Initial laboratory screening helps remove clearly unsuitable candidates before conducting more expensive printing or production trials.

Basic screening checks

• Powder or liquid appearance
• Dispersion behavior and lump formation
• Hydration time and mixing requirement
• Solution or paste uniformity
• Viscosity under the agreed test method
• pH under the defined preparation condition
• Filtration or screen-residue behavior
• Foam, separation, settling or skin formation
• Viscosity after the normal holding period

Each candidate should have a unique sample code and preparation record. Avoid using informal descriptions such as “sample one” or “white powder” when several grades are being evaluated.

Do not approve a grade from water testing alone

A thickener solution prepared only with water can be useful for basic screening, but it does not represent the complete printing paste. Electrolytes, alkali, binders, dyes, pigments and other auxiliaries may change viscosity and stability.

Step 6: Test the Complete Formulation

After initial screening, prepare the candidate in the actual or representative production formulation. Keep the formulation unchanged unless dosage adjustment is part of the planned test design.

Control the formulation variables

• Thickener dosage
• Dye, pigment or ink concentration
• Alkali, salt, binder and main auxiliaries
• Ordre d'addition
• Mixing and hydration procedure
• Process-water source
• Paste holding time
• Final pH and viscosity measurement

During the first comparison, change only one major variable at a time. Changing the thickener, dosage, dye concentration, alkali, fixation and washing process together makes it difficult to identify the cause of the final result.

Evaluate paste stability over time

Measure the paste immediately after preparation and again after the normal factory holding period. Record viscosity drift, separation, settling, foaming or changes after the complete auxiliary package is added.

Step 7: Run a Controlled Application Trial

Once the candidate passes preparation and stability screening, conduct a controlled application trial. The reference and candidate should be tested with the same fabric, colorant concentration, machine settings, fixation process and post-treatment sequence.

Comportement d'impression à observer

• Screen passage, release or filtration
• Paste transfer and machine handling
• Définition du contour et saignement
• Pénétration et couverture de surface
• Obstruction du tamis ou formation de dépôts
• Stabilité de la mousse et de la pâte pendant le cycle de production
• Consistency from the beginning to the end of the trial

A laboratory drawdown, hand-screen test or small coating trial may be used for the first comparison. However, it should not automatically replace a production-relevant machine trial when the commercial process involves different shear, pressure, speed or drying conditions.

Use the approved product as a control

Include the current approved grade in the same trial wherever possible. This helps separate candidate performance from normal variation in fabric, dye, water and equipment.

Step 8: Evaluate the Final Textile Result

The grade-matching decision should be based on the final textile result, not only on paste viscosity or machine behavior. Apply the same fixation, drying, washing and finishing conditions to the reference and candidate.

Final performance criteria may include

• Réponse aux nuances et cohérence visuelle
• Netteté d'impression et définition des contours
• Pénétration et couverture de surface
• Levelness across the printed area
• Comportement au lavage et résidus de pâte
• Fabric handle after post-treatment
• Résultats pertinents concernant la résistance au frottement ou la solidité des couleurs
• Post-treatment efficiency and production practicality

Fastness and shade results depend on the complete textile process and should not be attributed to the thickener alone. Any numerical claim should identify the test method, control product and trial conditions.

Test representative production conditions

Where the factory produces different shades or fabric qualities, select more than one representative condition. A grade approved with one light shade may still require confirmation in a heavier or chemically different formulation.

Étape 9 : Comparer le coût d'utilisation et la facilité de fabrication

Price per kilogram does not show the full operating cost of a textile chemical. A candidate may have a lower purchase price but require a higher dosage, longer mixing, additional filtration or more washing.

Cost-in-use factors to review

• Dosage needed to reach the required paste performance
• Mixing time, hydration time and energy requirement
• Filtration and screen-cleaning requirements
• Paste loss during preparation or production
• Machine interruption or blockage risk
• Washing and rinsing requirements
• Reprocessing or rejected-fabric risk
• Emballage, stockage et gestion des stocks
• Technical documentation and supplier support

The lowest-priced grade is not automatically the lowest-cost production option. The final decision should balance application performance, process reliability, documentation and commercial conditions.

Step 10: Verify the Commercial Batch

Laboratory approval is an important milestone, but it does not complete the qualification. The approved sample must be connected to a permanent commercial grade, specification and batch-release procedure.

Lock the approved product identity

The approved sample, TDS, quotation, purchase order, package label and COA should use the same product and grade code. Avoid approving one specific sample and then purchasing only by a general chemical-family name.

Confirm the first-batch control plan

• Parameters that will appear on the batch COA
• Incoming tests to be completed by the buyer
• Required retention samples
• Packaging and label requirements
• Acceptance limits for the first commercial delivery
• Procedure for reporting an out-of-specification result

Conduct incoming inspection

Check packaging, batch number, product appearance and documents before releasing multiple packages to production. Complete the agreed viscosity or application test before using the entire shipment.

Monitor the first production runs

Record preparation, dosage, paste viscosity, machine behavior, final textile result and wash-off performance. These records create a practical baseline for future batch monitoring.

Manage future product changes

If the agreed specification, raw-material route or manufacturing process changes significantly, part of the qualification may need to be repeated. Change-notification expectations should be discussed during commercial approval.

Grade Matching Decision Gates

Documents Required for Grade Approval

During initial technical review

• Current TDS for the candidate grade
• Current SDS for handling and internal review
• Sample label and permanent grade code
• Recommended preparation and hydration method
• Complete viscosity measurement procedure
• Relevant specification parameters and units

After sample approval

• Agreed commercial specification
• Approved product and grade code
• Packaging and label specification
• Required batch-control parameters
• Change-notification expectations where agreed

For commercial shipment

• Batch-specific Certificate of Analysis
• Commercial invoice and packing list
• Required origin or shipping documents
• Product and batch identification

A COA confirms only the parameters reported on that document. It does not replace the buyer’s application trial or guarantee identical performance under every formulation and production condition.

Certifications should be requested only where relevant. Buyers should verify the certificate holder, product scope, issuer and validity period before relying on a document for approval.

Common Grade Matching Mistakes

Matching only by product name

CMC, CMS and sodium alginate are product families rather than complete specifications. A product-family name cannot confirm viscosity method, hydration behavior or application suitability.

Comparing viscosity from different methods

Viscosity values measured at different concentrations, temperatures, spindle settings or rotational speeds should not be treated as directly comparable.

Providing an unrepresentative reference sample

A humid, contaminated or outdated sample may lead to the wrong matching direction. Provide the current TDS and a representative batch wherever possible.

Changing several process variables at once

Changing dosage, alkali, dye, fixation and washing together prevents the technical team from isolating the effect of the candidate grade.

Testing only the candidate

Without the current approved product as a control, normal variation in fabric, water or equipment may be incorrectly attributed to the new chemical.

Ignoring process-water quality

A candidate prepared with laboratory water may behave differently under factory conditions. Use actual process water or include a separate water-sensitivity comparison where practical.

Approving a custom sample without a production plan

Confirm that the approved sample can be reproduced as a permanent commercial grade with a defined specification and batch-release method.

Comparing price before dosage and performance

A lower price per kilogram does not guarantee a lower cost per batch. Include dosage, preparation, cleaning, washing and reprocessing in the comparison.

How FSX Chemical Supports Grade Matching

FSX Chemical supplies CMC, CMS, sodium alginate, digital printing paste and matched thickener routes for textile printing applications. The starting product direction can be reviewed according to the customer’s fabric, colorant system, process and current production issue.

Information buyers can provide

• Nom actuel du produit, fiche technique (TDS) ou échantillon représentatif
• Fabric and fibre composition
• Système à base de colorant, de pigment ou d'encre
• Méthode d'impression et type de machine
• Current dosage and preparation procedure
• Viscosité cible selon la méthode d'essai complète
• Main issue to be addressed
• Required packaging, order volume and destination📧 E-mail: Service@fsxchemical.com

Based on the available information, the technical team can review the suitable product route and prepare a candidate sample for laboratory evaluation. TDS and SDS can be provided for the selected grade, while batch-specific COA information should be confirmed against the actual commercial batch.

Final approval should remain based on the customer’s own laboratory or production trial. Results can vary with the formulation, water quality, fabric, equipment, fixation and washing conditions.