Section 2 Tests on polymers, resins, reinforcements and associated materials

2.1.1 This Section gives the tests and data required by LR for materials approval and/or inspection purposes on the following:

1. Thermoplastic polymers.

2. Thermosetting resins.

3. Reinforcements.

4. Reinforced thermoplastic polymers.

5. Reinforced thermosetting resins.

6. Core materials.

   1. End-grain balsa.

   2. Rigid foams.

   3. Synthetic felt type materials.

7. Machinery chocking compounds.

8. Rudder and pintle bearings.

9. Sterntube bearings.

10. Plywoods.

11. Adhesive and sealant materials.

12. Repair compounds.

2.2.1 The following data is to be provided by the manufacturer for each thermoplastic polymer:

1. Melting point.

2. Melt flow index.

3. Density.

4. Bulk density.

5. Filler content, where applicable.

6. Pigment content, where applicable.

7. Colour.

2.2.2 Samples for testing are to be prepared by moulding or extrusion under the polymer manufacturer's recommended conditions.

2.2.3 The following tests are to be carried out on these samples:

1. Tensile stress at yield and break.

2. Modulus of elasticity in tension.

3. Tensile strain at yield and break.

4. Compressive stress at yield and break.

5. Compressive modulus.

6. Temperature of deflection under load.

7. Determination of water absorption.

2.3.1 The data listed in Table 14.2.1 Data requirements for thermosetting resins is to be provided by the manufacturer for each thermosetting resin.

2.3.2 Cast samples are to be prepared in accordance with the manufacturer's recommendations and are to be cured and post-cured in a manner consistent with the intended use. The curing system used and the ratio of curing agent (or catalyst) to resin are to be recorded. Where post-cure conditions equivalent to ambient-cure conditions apply, see Ch 14, 3.2 Preparation of test samples 3.2.2 and Ch 14, 3.2 Preparation of test samples 3.2.3.

2.3.3 The following are to be determined using these samples:

1. Tensile strength (stress at maximum load) and stress at break.

2. Tensile strain at maximum load.

3. Tensile secant modulus at 0,5 per cent and 0,25 per cent strain respectively.

4. Temperature of deflection under load.

5. Barcol hardness.

6. Determination of water absorption.

7. Volume shrinkage after cure.

8. Specific gravity of cast resin.

2.3.4 In addition, for gel coat resins the stress at break and modulus of elasticity in flexure are to be determined.

2.3.5 Where resins which have been modified by the addition of waxes or polymers, for example ‘low styrene emission or air inhibited’ materials, it is to be confirmed that the use of such resins will not result in poor interlaminar adhesion when interruptions to the laminating process occur. The test procedure is to be as follows:

1. A conventional room temperature curing catalyst/ accelerator system is to be used with the resin for laminate preparation.

2. A laminate of 25 to 35 per cent glass content in mass is to be prepared using two plies of 450 g/m² chopped strand mat. The laminate is to be prepared at ambient temperature (18° to 21°C). The laminate is to be allowed to stand for a minimum of four days but no longer than 6 days at ambient temperature.

3. A further two plies of 450 g/m² chopped strand mat are to be laminated onto the exposed surface and cured at ambient temperature for 24 hours. The finished laminate is then to be post-cured at 40°C for 16 hours. The finished laminate is to have a glass content of 25 to 35 per cent.

4. After cooling, the apparent interlaminar shear strength of the laminate is to be determined in accordance with ISO 14130; the minimum value is given in Ch 14, 5.11 Minimum tested requirements for material approval 5.11.4. Before testing the samples shall be conditioned at 23°C and relative humidity of 50 per cent for a period of 88 hours before testing.

5. If the tests are undertaken at the resin manufacturer’s own laboratory, the individual test values are to be reported and the broken test specimens retained for examination by LR.

Alternative test procedures will be considered with prior agreement.

2.4.1 The following data is to be provided, where applicable, for each type of reinforcement:

1. Reinforcement type.

2. Fibre type for each direction.

3. Fibre tex value.

4. Fibre finish and/or treatment.

5. Yarn count in each direction.

6. Width of manufactured reinforcement.

7. Weight per unit area of manufactured reinforcement.

8. Weight per linear metre of manufactured reinforcement.

9. Compatibility (e.g. suitable for polyesters, epoxides, etc.).

10. Constructional stitching – details of yarn, specific gravity, type, frequency and direction.

11. Weave type.

12. Binder type and content.

13. Density of the fibre material.

2.4.2 Tests of the mechanical properties are to be made on laminate samples containing the reinforcement and prepared as follows:

1. an approved resin of suitable type is to be used;

2. a minimum of three layers of the reinforcement is to be laid with parallel ply to give a laminate not less than 4 mm thick;

3. the weights of resin and reinforcement used are to be recorded together with the measured thickness of the laminate, including the measured weight per unit area of the reinforcement used;

4. for glass reinforcements, the glass/resin ratios, by weight, as shown in Table 14.2.2 Glass fraction by weight for different reinforcement types are to be used;

5. for reinforcement type other than glass, a fibre volume fraction, as shown in Table 14.2.3 Content by volume for different reinforcement types, is to be used.

2.4.3 Rovings intended for filament winding are to be tested as unidirectional rovings.

2.4.4 The following tests as defined in Ch 14, 3 Testing procedures are to be made on the samples:

1. Tensile strength (stress at maximum load).

2. Tensile strain at break.

3. Tensile secant modulus at 0,5 per cent and 0,25 per cent strain respectively.

4. Compressive strength (stress at maximum load).

5. Compressive modulus.

6. Flexural strength (stress at maximum load).

7. Modulus of elasticity in flexure.

8. Apparent interlaminar shear.

9. Fibre content.

10. Determination of water absorption.

2.4.5 The laminate is to be tested in air in the directions indicated by Table 14.2.4 Fibre orientations in reinforced test specimens.

2.4.6 Additionally, tests in Ch 14, 2.4 Reinforcements 2.4.4(c) and (f) are to be repeated, in one direction only, after immersion in fresh water at 35°C for 28 days with the exception of Ch 14, 2.4 Reinforcements 2.4.4(j).

2.5.1 Thermoplastic polymers intended for use with reinforcements are to be tested in accordance with Ch 14, 2.2 Thermoplastic polymers 2.2.1 to Ch 14, 2.2 Thermoplastic polymers 2.2.3.

2.5.2 A laminate is to be prepared using the polymer and an approved reinforcement in accordance with a manufacturing specification. The laminate is to be tested in accordance with the appropriate requirements of Ch 14, 2.4 Reinforcements 2.4.4. Testing may be confined to one direction only.

2.6.1 Thermosetting resins intended for use with reinforcements are to be tested in accordance with Ch 14, 2.3 Thermosetting resins 2.3.1 to Ch 14, 2.3 Thermosetting resins 2.3.4.

2.6.2 No further tests are required for gel coat resins.

2.6.3 For laminating resins, a laminate is to be prepared using the resin and an approved reinforcement as follows:

1. For polyester resins, chopped strand mat.

2. For epoxide resins, a balanced woven roving.

3. For phenolic resins, a balanced woven material.

2.6.4 The laminate is to be tested in accordance with procedures outlined in MQPS Book K procedure 14-1 and Ch 14, 2.4 Reinforcements 2.4.4 in one fibre direction only.

2.7.1  General requirements. The following data is to be provided for each type of core material:

1. Type of material.

2. Density.

3. Description (block, scrim mounted, grooved).

4. Thickness and tolerance.

5. Sheet/block dimensions.

6. Surface treatment.

2.7.2 Manufacturers are required to provide a full application procedure for use of the product.

2.8.1 The supplier is to provide a signed statement that the balsa (ochroma lozopus) is cut to end-grain, is of good quality, being free from unsound or loose knots, holes, splits, rot, pith and corcho, and that it has been treated against fungal and insect attack, shortly after felling, followed by homogenisation, sterilisation and kiln drying to an average moisture content of no more than 12 per cent.

2.8.2 The following tests are to be carried out on the virgin material, both parallel to and perpendicular to the grain:

1. Compressive strength (stress at maximum load).

2. Compressive modulus of elasticity.

3. Tensile strength (stress at maximum load).

The density of the virgin material is also to be tested.

2.8.3 Where the balsa is mounted on a carrier material (e.g. scrim), any adhesive used is to be of a type compatible with the proposed resin system.

2.8.4 Core shear properties are to be determined according to the requirements of Ch 14, 3.8 Structural core materials 3.8.1.

2.9.1 The foam is to be of the closed cell type and compatible with the proposed resin system (e.g. polyester, epoxide etc.).

2.9.2 Foams are to be of uniform cell structure.

2.9.3 Data is to be provided on the dimensional stability of the foam by measurement of the shrinkage.

2.9.4 The following test data is to be submitted for each type of foam:

1. Density.

2. Tensile strength (stress at maximum load).

3. Tensile modulus of elasticity.

4. Compressive strength (stress at maximum load).

5. Compressive modulus of elasticity.

2.9.5 Core shear properties are to be determined according to the requirements of Ch 14, 3.8 Structural core materials 3.8.1.

2.9.6 Additionally, the compressive properties (see Ch 14, 2.9 Specific requirements for rigid foams (PVC, Polyurethane and other types) 2.9.4.(d) and Ch 14, 2.9 Specific requirements for rigid foams (PVC, Polyurethane and other types) 2.9.4.(e)) are to be determined at a minimum of five points over the temperature range ambient to maximum recommended service or 70°C, whichever is the greater.

2.10.1 For materials of this type, the following data is required in addition to the requirements of Ch 14, 2.7 Core materials 2.7.1:

1. Fibre type.

2. Width.

3. Width of finished material.

4. Weight per unit area of the manufactured material.

5. Weight per linear metre of the manufactured material.

6. Compatibility.

7. Details of the method of combining.

2.10.2 A laminate of the material is to be prepared using a suitable approved resin under conditions recommended by the manufacturer.

2.10.3 The following properties are to be determined:

1. Tensile strength (stress at maximum load).

2. Tensile strain at break.

3. Modulus of elasticity in tension or secant modulus at 0,25 per cent and 0,5 per cent strain.

4. Compressive strength (stress at maximum load).

5. Compressive modulus.

6. Flexural strength (stress at maximum load).

7. Modulus of elasticity in flexure.

8. Fibre content.

9. Water absorption.

2.10.4 In the case of anisotropic materials (e.g. where combined with other reinforcements) the tests listed in Ch 14, 2.10 Synthetic felt type materials with or without microspheres 2.10.3 are to be conducted in the 0°, 90° directions and in any other reinforcement direction.

2.10.5 Additionally, the tests listed in Ch 14, 2.10 Synthetic felt type materials with or without microspheres 2.10.3 are to be repeated after immersion in fresh water at 35°C for 28 days. For anisotropic materials, the requirement is for this test to be carried out in one direction only.

2.10.6 The shear properties (of the resin filled system) are to be determined according to Ch 14, 3.8 Structural core materials 3.8.1.

2.11.1 Thermosetting materials for filling the space between the base of machinery and its foundation where the maintenance of accurate alignment is necessary are to be approved by LR before use.

2.11.2 Approval will be considered by LR for use under the following service conditions:

• Loading of 3,5 N/mm² (max) for a temperature not exceeding 60°C.
• Loading of 2,5 N/mm² (max) for a temperature not exceeding 80°C.
• Other loading conditions.

2.11.3 The exotherm temperature, defined as the maximum temperature achieved by the reacting resin under conditions equivalent to those of intended use, is to be determined according to a procedure approved by LR.

2.11.4 The following properties are to be determined on chock material cured at the measured exotherm temperature:

1. The impact resistance (Izod).

2. Hardness.

3. Compressive strength (stress at maximum load) and modulus of elasticity.

4. Water absorption.

5. Oil absorption.

6. Heat deflection temperature.

7. Compressive creep is to be measured according to Ch 14, 3.9 Machinery chocking compounds 3.9.4.

8. Curing linear shrinkage.

9. Flammability.

2.11.5 The chocking compound approval is contingent on the material achieving the minimum exotherm value as specified when used on an installation under practical conditions.

2.11.6 Where the resin chock is to be used for installation of sterntubes and sternbushes in addition to the requirements of Ch 14, 2.11 Machinery chocking compounds (resin chocks) 2.11.4, the tensile strength and modulus of elasticity in tension are to be measured.

2.11.7 The manufacturer's installation procedure is required to be documented and is to be to the satisfaction of LR.

2.11.8 Resin chock materials are to be tested in accordance with Ch 14, 3.9 Machinery chocking compounds and are to meet the requirements of Ch 14, 5.14 Synthetic chocking compounds.

2.12.1 Materials used for rudder and pintle bearings are to be approved by LR before use.

2.12.2 Initial approval is to be based on a review of the following physical properties of the material:

1. Compressive strength (stress at maximum load) and modulus of elasticity.

2. Tensile strength (stress at maximum load) and modulus of elasticity.

3. Shear strength (stress at maximum load).

4. Impact strength.

5. Swelling in oil and in water.

6. Hardness.

2.12.3 Additionally, friction data is to be provided under both wet and dry conditions.

2.12.4 Furthermore, the installation instructions (especially recommended clearances) are to be reviewed by LR prior to provisional approval being given.

2.12.5 If the above data is satisfactory, the material will be provisionally approved until sufficient service experience has been gained.

2.13.1 Materials used for sterntube bearings are to be approved by LR before use.

2.13.2 Approval is to be based on a review of the physical properties as given by Ch 14, 2.12 Rudder and pintle bearings 2.12.2.

2.13.3 Friction data is to be provided under the lubrication system(s) proposed for the material(s).

2.14.1 All plywoods are to be approved to BS 1088 or equivalent National or International Standard in accordance with LR's Type Approval Procedure.

2.14.2 For structural applications in the marine environment, a minimum timber rating of moderate durability according to BS 1088 is required.

2.14.3 Enhancement of durability by use of preservatives is permitted, subject to each veneer layer being treated with a recognised preservative.

2.14.4 Where Okoume, as specified by BS 1088 is involved, (i.e. non-durable timber classification) this may only be used for marine structures subject to the specific application being acceptable to LR.

2.15.1 Materials of these types are to be accepted by LR before use.

2.15.2 The requirements for acceptance are dependent on the nature of the application.

2.15.3 In the first instance, the manufacturer is to submit full details of the product, procedure for method of use (including surface preparation) and the intended application. After review of these details, LR will provide a specific test schedule for confirmation of the material's properties.

2.15.4 Any acceptance granted will be limited to specific applications and will be contingent on the instructions for use being adhered to.

2.16.1 Materials used for repairs are to be accepted by LR before use.

2.16.2 For acceptance purposes, the manufacturer is to submit full product details and user instructions, listing the types of repair for which the system is to be used together with details of any installer accreditation schemes.

2.16.3 Dependent on the proposed uses, LR may require testing in accordance with a specified test programme.

2.16.4 Materials will not be accepted for the following uses unless specific evidence of their suitability is provided:

1. Any component in rubbing contact.

2. Any component subject to dynamic cyclic loading.

3. Any pressure part in contact with gas or vapour.

4. Any pressure part in contact with liquid above 0,35 MPa.

5. Any component where operating temperature exceeds 90°C.

All uses of materials of these types are subject to the discretion of the Surveyor.