ASTM D4690-12(2018)

Standard Specification for Urea-Formaldehyde Resin Adhesives

ABSTRACT
This specification covers three types of urea-formaldehyde thermosetting resin adhesives suitable for use on wood, wood-based substrates, or plastic laminates. The requirements for the adhesive are based on tests of physical properties including viscosity, density, nonvolatile content, pH, insoluble matter, amylaceous matter, mixing properties, working life, and on strength properties, including dry shear strength in lumber-type joints, dry and wet shear strength in plywood-type joints, and all strength tests at the end of the storage life certified by the manufacturer. Testing procedures are specified to differentiate between the physical and adhesive bonding properties of the many commercial urea-formaldehyde thermosetting resin and catalyst systems. The adhesive bonding properties are measured on maple block and birch plywood specimens, prepared and tested in accordance with prescribed methods.
SCOPE
1.1 This specification covers three types of urea-formaldehyde thermosetting resin adhesives suitable for use on wood, wood-based substrates, or plastic laminates.  
1.2 The values stated in SI units are to be regarded as the standard. The values given in parentheses are provided for information only.  
1.3 The requirements for the adhesive are based on tests of physical properties including viscosity, density, nonvolatile content, pH, insoluble matter, amylaceous matter, mixing properties, working life, and on strength properties, including dry shear strength in lumber-type joints, dry and wet shear strength in plywood-type joints, and all strength tests at the end of the storage life certified by the manufacturer.  
1.4 The following safety hazards caveat pertains only to the test method portion, Sections 8 through 11, of this specification: This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.  
1.5 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

General Information

• Status: Published
• Publication Date: 31-Jul-2018
• ICS: 83.180 - Adhesives
• Technical Committee: D14 - Adhesives
• Drafting Committee: D14.30 - Wood Adhesives

Relations

• Replaces: ASTM D4690-12 - Standard Specification for Urea-Formaldehyde Resin Adhesives
• Effective Date: 01-Aug-2018
• Refers: ASTM E70-24 - Standard Test Method for pH of Aqueous Solutions With the Glass Electrode
• Effective Date: 01-Jan-2024
• Refers: ASTM D906-20 - Standard Test Method for Strength Properties of Adhesives in Plywood Type Construction in Shear by Tension Loading
• Effective Date: 01-Apr-2020
• Refers: ASTM D5266-13(2020) - Standard Practice for Estimating the Percentage of Wood Failure in Adhesive Bonded Joints
• Effective Date: 01-Apr-2020
• Refers: ASTM D2556-14(2018) - Standard Test Method for Apparent Viscosity of Adhesives Having Shear-Rate-Dependent Flow Properties Using Rotational Viscometry
• Effective Date: 01-Nov-2018
• Refers: ASTM D1875-03(2018) - Standard Test Method for Density of Adhesives in Fluid Form
• Effective Date: 01-Nov-2018
• Refers: ASTM D1583-01(2018) - Standard Test Method for Hydrogen Ion Concentration of Dry Adhesive Films
• Effective Date: 01-Aug-2018
• Refers: ASTM D1490-01(2018) - Standard Test Method for Nonvolatile Content of Urea-Formaldehyde Resin Solutions
• Effective Date: 01-Aug-2018
• Refers: ASTM D906-98(2017) - Standard Test Method for Strength Properties of Adhesives in Plywood Type Construction in Shear by Tension Loading
• Effective Date: 01-Aug-2017
• Refers: ASTM E70-07(2015) - Standard Test Method for pH of Aqueous Solutions With the Glass Electrode
• Effective Date: 01-Jun-2015
• Refers: ASTM D2556-14 - Standard Test Method for Apparent Viscosity of Adhesives Having Shear-Rate-Dependent Flow Properties Using Rotational Viscometry
• Effective Date: 01-Mar-2014
• Refers: ASTM D1583-01(2013) - Standard Test Method for Hydrogen Ion Concentration of Dry Adhesive Films
• Effective Date: 01-Oct-2013
• Refers: ASTM D1875-03(2013) - Standard Test Method for Density of Adhesives in Fluid Form
• Effective Date: 01-Oct-2013
• Refers: ASTM B417-13 - Standard Test Method for Apparent Density of Non-Free-Flowing Metal Powders Using the Carney Funnel
• Effective Date: 01-Oct-2013
• Refers: ASTM D5266-13 - Standard Practice for Estimating the Percentage of Wood Failure in Adhesive Bonded Joints
• Effective Date: 01-May-2013

Overview

ASTM D4690-12(2018): Standard Specification for Urea-Formaldehyde Resin Adhesives provides comprehensive requirements for the classification and testing of urea-formaldehyde thermosetting resin adhesives. Developed by ASTM International, this standard establishes criteria for three adhesive types specifically designed for use on wood, wood-based substrates, or plastic laminates. The primary objective is to ensure the quality, performance, and reliability of adhesives through detailed testing of both physical and adhesive-bonding properties.

Urea-formaldehyde resin adhesives are widely recognized for their strong bonding capabilities and cost-effectiveness in the wood products industry. This specification outlines the necessary test methods and quality benchmarks to guide both manufacturers and end-users in evaluating and certifying product quality.

Key Topics

• Adhesive Types: The standard categorizes adhesives as:

  • Type A: Powder with separate curing agent
  • Type B: Powder with incorporated curing agent
  • Type C: Liquid with separate curing agent

• Testing Requirements: Adhesives must meet rigorous criteria based on tests including:

  • Viscosity
  • Density
  • Nonvolatile content
  • pH
  • Insoluble matter
  • Amylaceous matter
  • Mixing properties
  • Working life

• Strength Properties: Critical performance aspects are validated with:

  • Dry shear strength in lumber-type joints
  • Dry and wet shear strength in plywood-type joints
  • Tests conducted after the manufacturer's certified storage life

• Sampling and Reporting: Instructions are provided for representative sampling, report formats, and manufacturer certifications.

• Safety Considerations: Users are responsible for adhering to appropriate safety, health, and environmental practices during testing and use.

Applications

Urea-formaldehyde resin adhesives specified by ASTM D4690 are ideal for a wide range of wood and composite bonding applications, including:

• Plywood Manufacturing: Ensuring robust and durable bonds for structural and decorative plywood.
• Laminated Wood Products: Reliable adhesion for panels, flooring, furniture, and cabinetry.
• Wood-based Substrates: Suitable for particleboards, fiberboards, and other engineered wood products.
• Plastic Laminates: Versatile use where plastic overlays or surfaces are bonded to wood or composites.

The standard ensures adhesives meet critical performance parameters, supporting quality assurance in both large-scale manufacturing and specialized woodworking projects.

Related Standards

ASTM D4690 references and aligns with a number of related test methods and terminology standards to offer a consistent approach across the adhesives sector, including:

• ASTM D905: Test Method for Strength Properties of Adhesive Bonds in Shear by Compression Loading
• ASTM D906: Test Method for Strength Properties of Adhesives in Plywood Type Construction in Shear by Tension Loading
• ASTM D907: Terminology of Adhesives
• ASTM D1084 / D2556: Test Methods for Viscosity of Adhesives
• ASTM D1489 / D1490: Test Method for Nonvolatile Content of Urea-Formaldehyde Resin Solutions
• ASTM D1583: Test Method for Hydrogen Ion Concentration of Dry Adhesive Films
• ASTM D1875: Test Method for Density of Adhesives in Fluid Form
• ASTM E70: Test Method for pH of Aqueous Solutions

Other key references include federal and military standards for packaging, labeling, and shipping to ensure compatibility with commercial and government procurement requirements.

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Keywords: urea-formaldehyde resin adhesive, wood adhesive, thermosetting resin, ASTM D4690, adhesive strength testing, plywood adhesive, adhesive viscosity, wood-based substrates, nonvolatile content, adhesive standards.

Standards Content (Sample)

This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the
Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
Designation: D4690 −12 (Reapproved 2018)
Standard Specification for
Urea-Formaldehyde Resin Adhesives
This standard is issued under the fixed designation D4690; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
This standard has been approved for use by agencies of the U.S. Department of Defense.
1. Scope B417 Test Method for Apparent Density of Non-Free-
Flowing Metal Powders Using the Carney Funnel
1.1 This specification covers three types of urea-
D905 Test Method for Strength Properties of Adhesive
formaldehyde thermosetting resin adhesives suitable for use on
Bonds in Shear by Compression Loading
wood, wood-based substrates, or plastic laminates.
D906 Test Method for Strength Properties of Adhesives in
1.2 The values stated in SI units are to be regarded as the
Plywood Type Construction in Shear by Tension Loading
standard. The values given in parentheses are provided for
D907 Terminology of Adhesives
information only.
D1084 Test Methods for Viscosity of Adhesives
1.3 The requirements for the adhesive are based on tests of D1489 Test Method for Nonvolatile Content of Aqueous
Adhesives
physical properties including viscosity, density, nonvolatile
content, pH, insoluble matter, amylaceous matter, mixing D1490 Test Method for Nonvolatile Content of Urea-
Formaldehyde Resin Solutions
properties, working life, and on strength properties, including
dry shear strength in lumber-type joints, dry and wet shear D1583 Test Method for Hydrogen Ion Concentration of Dry
Adhesive Films
strengthinplywood-typejoints,andallstrengthtestsattheend
of the storage life certified by the manufacturer. D1875 Test Method for Density ofAdhesives in Fluid Form
D2556 Test Method for Apparent Viscosity of Adhesives
1.4 The following safety hazards caveat pertains only to the
Having Shear-Rate-Dependent Flow Properties Using Ro-
test method portion, Sections 8 through 11, of this specifica-
tational Viscometry
tion: This standard does not purport to address all of the safety
D5266 Practice for Estimating the Percentage of Wood
concerns, if any, associated with its use. It is the responsibility
Failure in Adhesive Bonded Joints
of the user of this standard to establish appropriate safety,
E70 Test Method for pH of Aqueous Solutions With the
health, and environmental practices and determine the appli-
Glass Electrode
cability of regulatory limitations prior to use.
E104 Practice for Maintaining Constant Relative Humidity
1.5 This international standard was developed in accor-
by Means of Aqueous Solutions
dance with internationally recognized principles on standard-
2.2 Federal Specifications:
ization established in the Decision on Principles for the
PPP-C-96 Cans, Metal, 28 Gage and Lighter
Development of International Standards, Guides and Recom-
PPP-D-723 Drums, Fiber
mendations issued by the World Trade Organization Technical
PPP-D-729 Drums, Shipping and Storage, Steel, 55-gal
Barriers to Trade (TBT) Committee.
(208-L)
2. Referenced Documents
2.3 Federal Standard:
FED-STD-123 Marking for Shipment
2.1 ASTM Standards:
2.4 Military Standard:
MIL-STD-129 Marking for Shipment and Storage
This specification is under the jurisdiction of ASTM Committee D14 on
Adhesives and is the direct responsibility of Subcommittee D14.30 on Wood
3. Terminology
Adhesives.
3.1 Definitions—Many terms in this specification are de-
Current edition approved Aug. 1, 2018. Published August 2018. Originally
approved in 1987. Last previous edition approved in 2012 as D4690 – 12. DOI:
fined in Terminology D907.
10.1520/D4690-12R18.
3.2 Definitions of Terms Specific to This Standard:
This specification is intended as a replacement for Federal Specification
MMM-A-188c, Adhesive; Urea Resin Type (Liquid and Powder).
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM Available from Standardization Documents Order Desk, DODSSP, Bldg. 4,
Standards volume information, refer to the standard’s Document Summary page on Section D, 700 Robbins Ave., Philadelphia, PA 19111-5098, http://
the ASTM website. dodssp.daps.dla.mil.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D4690 − 12 (2018)
TABLE 1 Test Requirements
3.2.1 lot—adhesive manufactured at one place from the
same batch or blends of raw materials subjected to the same Test Requirement
Test Section Number
(Minimum)
operations and conditions.
Block shear (compression)
NOTE 1—In this specification, the maple block lamination in Test Dry at 24°C (75°F) 11.1 19 306 kPa (2800 psi)
Plywood shear (tension)
Method D905 and the birch plywood construction in Test Method D906
Dry at 24°C (75°F) 11.2.3.1 2 344 kPa (340 psi)
are described as assemblies.
48-h soak 11.2.3.2 1 930 kPa (280 psi)
A
Storage life 11.2.3.3
4. Significance and Use
A
A retained sample of the initial lot of the adhesive shall be tested and shall meet
the requirements of all tests listed in 6.2 for the applicable type of adhesive after
4.1 Thisspecificationprovidestestingproceduresandspeci-
the storage life time certified by the manufacturer.
fies requirements to differentiate between the physical and
adhesive bonding properties of the many commercial urea-
formaldehyde thermosetting resin and catalyst systems.
4.2 Because of the diverse nature of products bonded with
6.4 The filler shall neither dissolve nor swell excessively in
these adhesives, testing by this specification will only evaluate
water, and shall not settle from the adhesive mixture during the
the adhesive under a given set of conditions. The physical
working life.
properties of the adhesive are measured to provide information
on certain handling and working properties. The adhesive- 7. Retest and Rejection
bonding properties are measured on maple block and birch
7.1 When a specimen fails at a load less than that specified,
plywood specimens, prepared and tested in accordance with
if the wood failure is 50 % or greater, that specimen shall be
Test Method D905 and Test Method D906, respectively. The
disregardedincomputingtheaverage.Ifmorethanonethirdof
certification requirements have been based on knowledge
the test specimens for any one test condition are discarded for
within the industry of values that may be expected. Test
this reason, the test shall be repeated.
Method D905 and Test Method D906 have a long history of
7.2 If the results of any initial test do not conform to the
use in many specifications.
requirements prescribed in this specification, that test shall be
4.3 The stress calculated by using this specification should
repeated on an additional set of specimens made from the same
not be used to predict failure nor should it be used for design
lot of adhesive, each set of which shall conform to the
stress in joints with different geometry or loading direction
requirementsspecified.Ifthissetofspecimensfailstomeetthe
different from the test geometry.
requirements, the lot shall be rejected.
5. Classification
TEST METHODS
5.1 Urea resin adhesive shall be furnished as one of the
following types:
8. Significance and Use
5.1.1 Type A—Powder with separate curing agent.
8.1 This specification provides testing procedures to differ-
5.1.2 Type B—Powder with incorporated curing agent.
entiate between the physical and adhesive bonding properties
5.1.3 Type C—Liquid with separate curing agent.
of the many commercial urea-formaldehyde thermosetting
NOTE 2—Type A, Type B, and Type C replace the Type I, Type II, and resin and catalyst systems.
Type III classifications of Federal Specification MMM-A-188C,
respectively, to prevent confusion with Type I (boil test) and Type II
9. Sampling
(cold-water soak) classifications used in existing ASTM standards for
9.1 Take a representative, 2-L (2-qt) sample of adhesive
adhesives.
from the lot to be tested. Divide the sample into two equal
portions and place each in a wide mouth, glass, 1-L (1-qt)
6. Test Requirements
container and seal tightly. Use one of the samples for tests of
6.1 To meet the requirements of this specification, the urea
physical and adhesive bond properties (Sections 10 and 11),
resin and adhesive mix shall be subjected to the tests listed in
and use the other for testing storage life (11.2.3.3), and for any
Section 10. In addition, the adhesive shall meet the require-
retesting that may be necessary under Section 7. Also, take
ments of the tests described in Section 11 and as listed in Table
sufficient quantity of curing agent to cure the adhesive samples
1.
and place in a separate, clean, dry container. Seal all sample
6.2 To meet the storage-life requirements, an initial lot of
containers with well-fitting, corrosion-resistant lids.
the adhesive shall be tested in accordance with Sections 10 and
11. It shall pass all test requirements after being stored under 10. Physical Properties
conditions and time specified by the manufacturer. Following
10.1 Test the physical properties of adhesives by the fol-
this initial test, certification shall be based on submission from
lowing test methods:
the manufacturer.
10.1.1 Viscosity:
6.3 The curing agent for Types A and C shall readily 10.1.1.1 Measure the viscosity of the liquid urea resin or
disperse in the adhesive mixture when used in accordance with adhesive mixtures in accordance with Test Methods D1084 or
the manufacturer’s recommendation. D2556.
D4690 − 12 (2018)
10.1.1.2 Temperature of Test—Condition to, and maintain adhesive mix on a porcelain spot plate or watch glass. A
the liquid urea resin or adhesive mixture at 24 6 0.5°C (75 6 darkening of the mixture denotes the presence of amylaceous
1°F) during the viscosity reading. Other temperatures may be matter.
used upon agreement between the contracting parties, but the 10.1.7 Mixing Properties and Working Life, Mix approxi-
mately 200 g of adhesive (in accordance with the manufactur-
60.5°C (61°F) tolerance must be observed.
er’sinstruction)ina400-mLbeaker(Note6)withastirringrod
10.1.1.3 For Type C adhesives requiring the addition of a
or blade.Allow the beaker to stand without a cover in air at 24
curing agent, make two viscosity measurements of the test
6 2.5°C (75 6 5°F). If necessary, place in a water bath to
adhesives (1) before the addition of curing agent, and (2) after
obtain the proper temperature. Stir the adhesive frequently and
the addition of the curing agent. The viscosity of urea resins
note the time at which the adhesive is considered no longer
following addition of curing agent to liquid resin is time-
spreadable. At the end of the working life, note whether the
dependent. Make the measurement 10 min after mixing.
adhesive is in a homogeneous condition. In case of doubt as to
10.1.2 Density:
whether the adhesive is spreadable, test the adhesive at 24 6
10.1.2.1 Measure the density of dry-powder adhesives or
2.5°C (75 6 5°F) using a Brookfield Viscometer. Consider the
separate curing agents in accordance with Test Method B417,
adhesive to be at the end of its working life when it reaches a
and report in grams per cubic centimetre (pounds per cubic
viscosity of 600 P(0.6 Pa·s). If the temperature of the bonding
foot). (See Appendix X1.)
operation is 32.2°C (90°F) or higher, the above test may be
10.1.2.2 Measure the density of Type C adhesives in accor-
conducted at 32.2°C (90°F).
...