| Product Identity | Adhesive gum type | Water-based gum, dextrin-based adhesive, starch adhesive, or natural gum adhesive | Clearly stated with composition and intended application | Supplier technical data sheet and ingredient declaration | Product name, grade, batch number, manufacturing date, and application range | The adhesive type should match the buyer’s substrate, coating process, and drying conditions. |
| Physical form | Powder, granule, paste, or ready-to-use liquid | Uniform appearance with no visible foreign matter or abnormal agglomeration | Visual inspection under normal lighting | Appearance, color, odor, and physical form | Color variation should be controlled when the adhesive is used on visible packaging or labels. |
| Solid content | Common liquid adhesive range: approximately 25–60% by mass, depending on formulation | Within the agreed specification, typically ±2 percentage points from the target | Oven-drying or moisture-balance method based on an agreed laboratory procedure | Measured solid content, test temperature, and test date | Solid content directly affects viscosity, drying time, tack, and bond development. |
| pH value | Often approximately pH 4.5–8.5 for water-based adhesive systems | Within the formulation-specific range and compatible with the substrate | Calibrated pH meter at 23 ± 2°C | pH value, test temperature, and calibration status | Extreme pH can damage sensitive paper, affect pigment stability, or accelerate equipment corrosion. |
| Bond Performance | Dry bond strength on paper-to-paper | Application-dependent; a cohesive paper-fiber tear is generally preferred over clean adhesive failure | At least 80% fiber tear or the buyer’s validated minimum force | Conditioned paper strips bonded with a controlled adhesive coat; tensile or peel testing using a calibrated universal testing machine | Bond strength result, substrate type, adhesive coat weight, curing time, and failure mode | Bond strength values are not comparable unless substrate, coat weight, pressure, drying time, and conditioning are controlled. |
| Lap-shear strength | Reported in N or MPa for defined substrates and bond geometry | Set a product-specific minimum after pilot validation; do not use an unspecified universal value | ASTM D1002 or ISO 4587, adapted for the selected substrate where appropriate | Average result, standard deviation, specimen dimensions, and test speed | Metal lap-shear methods may not represent paper, carton, textile, or porous-substrate performance. |
| Peel strength | Reported in N/25 mm or N/mm for flexible bonded materials | Stable peel result with no abrupt adhesive delamination during the agreed test period | ASTM D903 or ISO 8510-2, using an agreed peel angle and speed | Peel force, peel angle, peel speed, substrate, and conditioning environment | Useful for labels, tapes, laminates, envelopes, and flexible packaging applications. |
| Initial tack | Low, medium, or high tack depending on application | Sufficient grab for the production line without premature sticking to rollers or guides | Loop tack, probe tack, or application-specific rapid bond test | Initial tack rating or quantitative force result | Initial tack should be evaluated together with open time and final bond strength. |
| Water resistance | Low, moderate, or high resistance after complete drying | No unacceptable whitening, lifting, or bond loss under the buyer’s intended humidity or water exposure | Water immersion, humidity aging, or application-specific resistance test | Exposure duration, temperature, humidity, and bond failure observation | Water resistance is formulation-specific and should be confirmed on the actual production substrate. |
| Shelf Life and Stability | Declared shelf life | Commonly 6–12 months for unopened water-based adhesive products when properly stored | At least 6 months remaining at the shipment date unless otherwise agreed | Review of stability records and expiry-date control | Manufacturing date, expiry date, storage conditions, and batch traceability | Actual shelf life depends on preservatives, packaging, solids, temperature, and contamination control. |
| Viscosity stability | Product-specific; typically monitored in mPa·s or cP | Within ±10% of the approved reference value after storage testing | Brookfield viscometer at a defined spindle, speed, and temperature | Viscosity, spindle, rotational speed, temperature, and measurement time | Viscosity without test conditions is not suitable for supplier comparison. |
| Freeze-thaw stability | Water-based products may be sensitive to freezing | No permanent gelation, phase separation, or unacceptable viscosity change after agreed cycles | Controlled freeze-thaw cycling, commonly between approximately -5°C and 25°C | Number of cycles, temperatures, appearance, viscosity, and bond retest | Buyers in cold climates should request transport and warehouse temperature limits. |
| Storage temperature | Often 5–35°C for water-based adhesive products; supplier-specific limits apply | Storage range printed on packaging and supported by stability data | Packaging review and accelerated or real-time stability study | Recommended temperature, humidity limitation, and protection from direct sunlight | Do not freeze. Excessive heat can increase viscosity drift, skin formation, or microbial risk. |
| Microbiological stability | Controlled by preservatives, hygiene, and sealed packaging | No abnormal odor, gas formation, mold, or visible microbial growth | Total plate count, yeast and mold count, or other agreed microbiological methods | Microbiological results, sampling plan, and product preservation information | Microbial requirements should be stricter for food-contact-adjacent packaging or hygiene-sensitive uses. |
| COA Data Quality | Batch traceability | Unique lot number linked to production and quality records | 100% traceability from delivered container to manufacturing record | Document review and batch-record verification | Lot number, production date, quantity, packaging unit, and release status | Every shipment should be traceable without relying only on the purchase-order number. |
| COA test results | Actual batch results rather than only standard limits | Results shown with units, methods, specification limits, and pass/fail status | COA review against the approved product specification | Actual value, specification range, test method, analyst or laboratory identification | “Conforms” alone is insufficient for trend analysis and incoming-quality control. |
| Moisture content | Powder and granule products commonly require a defined moisture limit; liquid products are evaluated through solids content | Use the approved grade-specific limit, commonly controlled within a narrow range | Loss on drying or validated moisture analyzer method | Moisture percentage, sample mass, method, and test temperature | Moisture affects flowability, microbial risk, dissolution, and final adhesive concentration. |
| Viscosity and solids correlation | Both values reported for liquid products | Results consistent with the approved reference batch | Brookfield viscosity plus solids-content test under controlled conditions | Viscosity, solids, temperature, spindle, and rotational speed | Reporting both parameters helps identify dilution, over-concentration, or formulation drift. |
| Certificate authenticity | COA issued by the manufacturing quality department or an identified testing laboratory | Document matches the lot label and shipment documentation | Document-control review and random laboratory verification | Authorized signature or electronic approval, issue date, and document number | Independent verification is recommended for first orders, critical applications, and repeated deviations. |
| Testing and Approval | Incoming sample inspection | Appearance, packaging condition, lot identity, odor, and viscosity or moisture | No damaged containers, leakage, contamination, or identity mismatch | Sampling plan based on ISO 2859-1 or the buyer’s internal quality plan | Inspection record, sample quantity, acceptance level, and nonconformance report if applicable | Sampling should cover multiple containers when the shipment contains several lots or pallet positions. |
| Application trial | Actual production substrate, equipment, coat weight, line speed, and drying conditions | Meets bond, drying, machine-run, appearance, and rework requirements | Controlled pilot run using the buyer’s standard operating conditions | Substrate, coat weight, line speed, drying temperature, open time, and final result | Laboratory approval alone cannot replace a production-line trial. |
| Accelerated aging | Elevated-temperature or humidity exposure used for comparative screening | No unacceptable loss of bond or physical instability after the agreed exposure period | Buyer-defined accelerated aging protocol; report conditions clearly | Temperature, relative humidity, duration, preconditioning, and post-aging bond result | Accelerated aging is comparative and should not be treated as a direct shelf-life conversion without validation. |
| Supplier quality performance | On-time delivery, lot consistency, complaint rate, and corrective-action response | Consistent batches and documented corrective action within the agreed response time | Quarterly supplier scorecard and nonconformance review | Delivery records, deviation reports, corrective-action reports, and trend data | Commercial reliability should be evaluated alongside laboratory performance. |
| Packaging and Compliance | Packaging integrity | Sealed pails, drums, bags, or intermediate bulk containers appropriate for the product form | No leakage, swelling, broken seals, or moisture ingress | Visual inspection and packaging-drop or transport validation where required | Packaging material, net weight, seal type, pallet configuration, and handling instructions | Packaging must protect the adhesive from contamination, evaporation, and excessive temperature exposure. |
| Regulatory documentation | SDS, technical data sheet, ingredient or allergen statement where applicable | Documents supplied in the buyer’s required language and current revision | Document review against destination-market requirements | SDS revision date, hazard classification, transport information, and composition disclosure level | Additional declarations may be needed for food packaging, toys, cosmetics, or other regulated uses. |
| Restricted substances | Heavy metals, formaldehyde, residual solvents, phthalates, or other substances according to application | Complies with the buyer’s restricted-substance list and destination-market rules | Validated chemical analysis by an internal or independent laboratory | Test results, detection limits, analytical method, and laboratory identification | Requirements must be defined before quotation because testing scope varies by end use and market. |