Light photovoltaic module backboard flame-retardant coating and preparation method thereof

Abstract

The invention relates to a light photovoltaic module backboard flame-retardant coating and a preparation method thereof. Raw materials of the coating comprise the following components: aliphatic polyurethane acrylate, a phosphoric acid modified methacrylic acid oligomer, an intumescent flame retardant, polysiloxane, polysilazane, methyl phenyl silicone resin, MQ resin, hollow titanium dioxide, hollow ceramic microspheres, a silicate ceramic agglutinant, a curing agent, an ultraviolet light absorber, a leveling wetting agent, an antioxidant and a solvent. The components of the flame-retardant coating form a plurality of synergistic effects such as expansion-ceramic synergy, phosphorus-silicon synergy and silicon-silicon synergy, so that the coating realizes efficient flame retardance, high carbonization residue, high heat insulation and excellent mechanical properties.

Description

Technical Field

[0001] This invention belongs to the field of photovoltaic module technology, and specifically relates to a flame-retardant coating for a lightweight photovoltaic module backsheet and its preparation method. Background Technology

[0002] Traditional glass photovoltaic modules are too heavy, limiting their application in certain areas. Currently, lightweight modules using polymer materials to replace double-glazed glass are widely used, including low-load-bearing distributed rooftop photovoltaics, mobile energy and portable devices, building-integrated photovoltaics (BIPV), agricultural photovoltaics, and distinctive landscaping. However, traditional double-glazed modules use inorganic silicate materials with extremely high melting points (approximately 600-800℃), making them non-combustible. In contrast, lightweight polymer modules use polymer materials for both the front and back panels, which are flammable. In the event of a fire, the flames could directly ignite the inside and outside of the module, posing a significant risk.

[0003] While introducing flame-retardant components into the substrate of the front and back panels of lightweight components can improve the flame-retardant rating of the substrate, as the amount added increases, the weather resistance and mechanical properties of the substrate will inevitably decrease significantly, leading to failure. Therefore, coating the substrate surface with a flame-retardant coating is a better choice.

[0004] Patent CN201210059800.1 describes the preparation of a functionalized sol using the sol-gel method, which is then mixed with UV resin and additives to create a UV-curable organic-inorganic flame-retardant coating. This coating has a certain flame-retardant effect and is easy to apply. However, since both the front and back panels of lightweight photovoltaic panels are flammable, the fire spreads rapidly in the event of a fire, making this coating unsuitable for lightweight photovoltaic panels.

[0005] Patent CN201810501570.7 describes the preparation of an infrared-resistant heat-insulating coating using nano-titanium dioxide composite powder material. This coating reduces the temperature through a physical barrier and reflects a large amount of radiant heat from the flame back when combustion occurs, thus reducing the net heat absorption and lowering the temperature of the substrate surface. However, this coating does not have a flame-retardant effect; when combustion occurs, it only provides heat insulation and lowers the substrate temperature, without achieving the purpose of flame retardancy.

[0006] Patent CN202410697099.9 discloses a flame-retardant coating for photovoltaic panels, which is prepared by selecting a combination of organosilicon resin and polyester resin, isocyanate curing agent, ammonium polyphosphate, triazine charring agent and starch flame retardant compound, catalyst, organic solvent and filler. The system introduces ammonium polyphosphate and charring agent, which has a certain flame-retardant effect. However, its essence is still a polyurethane organic coating cured by hydroxypropyl isocyanate. If the photovoltaic module is burned, its flame-retardant performance is far from sufficient.

[0007] At present, there is no flame-retardant coating specially for light photovoltaic backboard on the market, so developing a flame-retardant coating suitable for light photovoltaic backboard has important practical application value. SUMMARY

[0008] The technical problem to be solved by the present application is to provide a light photovoltaic module backboard flame-retardant coating and a preparation method thereof.

[0009] The present application provides a light photovoltaic module backboard flame-retardant coating, the raw materials of which include the following components in mass fraction:

[0010] aliphatic polyurethane acrylate 5-10 parts;

[0011] phosphoric acid modified methacrylic acid oligomer 1-3 parts;

[0012] intumescent flame retardant 10-15 parts;

[0013] polysiloxane 5-10 parts;

[0014] polysilazane 5-10 parts;

[0015] methylphenyl silicone resin 5-10 parts;

[0016] MQ resin 5-10 parts;

[0017] hollow titanium dioxide 15-25 parts;

[0018] hollow ceramic microspheres 15-25 parts;

[0019] silicate ceramic sintering agent 15-30 parts;

[0020] curing agent 1-3 parts;

[0021] ultraviolet absorber 0.5-2 parts;

[0022] leveling wetting agent 0.2-0.5 parts;

[0023] antioxidant 0.2-0.5 parts;

[0024] and 30%-40% of the total mass fraction of the solvent.

[0025] Preferably, the aliphatic polyurethane acrylate is a bifunctional aliphatic polyurethane acrylate.

[0026] Preferably, the phosphoric acid modified methacrylic acid oligomer is one or several of RAYLOLK 1722 and GA 2600Y.

[0027] Preferably, the intumescent flame retardant is a mixture of ammonium polyphosphate, pentaerythritol, melamine. Further, the mass ratio of the ammonium polyphosphate, pentaerythritol, melamine is 1-5:1-5:1-5.

[0028] Preferably, the polysiloxane is one or more of Andisil SF 1421, Andisil SF 4546.

[0029] Preferably, the polysilazane is one or more of ZG-109, ZG-UV678, IOTA OPSZ 9150K, IOTA ST6.

[0030] Preferably, the methylphenyl silicone resin is one or more of Andisil SF 1230, SICO-P112, SICO-P212.

[0031] Preferably, the MQ resin is CF ® 90-7, Andisil MQOH 7, Andisil VQM 1, Andisil VQM 2050, Andisil VQM 1040.

[0032] Preferably, the hollow titanium dioxide is one or more of AEROXIDE® TiO2 P 25, AEROXIDE® TiO2 P 90, Photospheres™.

[0033] Preferably, the hollow ceramic microsphere is one or more of DM95-G750, W210, W410, W610.

[0034] Preferably, the silicate ceramic sintering agent is one or more of DCF-8, DCF-1.

[0035] Preferably, the curing agent is one or more of TPO, 184, 1173, 819, P16, Trigonox 21S, BPO, Trigonox C.

[0036] Preferably, the ultraviolet absorber is one or more of UV400, UV1164, UV329, UV1130.

[0037] Preferably, the leveling wetting agent is one or more of BYK333, Tego 2100, Tego 4100, WET 240, WET 270, BYK3510.

[0038] Preferably, the antioxidant is one or more of TP-10H, 323TP, 1010, 168, Irganox® B900, and ADEKA PEP-36.

[0039] Preferably, the solvent is one or more of ethyl acetate, acetone, and butyl acetate.

[0040] This invention also provides a method for preparing a flame-retardant coating on the backsheet of a lightweight photovoltaic module, comprising the following steps:

[0041] The components are mixed according to the formula and stirred at room temperature to obtain a coating; then it is applied to the back sheet of a lightweight photovoltaic module and cured to obtain a flame-retardant coating for the back sheet of a lightweight photovoltaic module.

[0042] Preferably, the lightweight photovoltaic module backsheet is one or more of CPC, PP-FRP, and fiberglass composite materials.

[0043] Beneficial effects

[0044] (1) The flame-retardant coating prepared by the present invention forms an organic-inorganic hybrid network. The components work together to achieve high-efficiency flame retardancy, high temperature resistance and heat insulation, forming a variety of synergistic flame retardancy such as expansion-ceramic synergy, phosphorus-silicon synergy, silicon-silicon synergy, etc., so that the coating achieves high-efficiency flame retardancy, high carbonization residue, high heat insulation and excellent mechanical properties.

[0045] (2) The present invention uses aliphatic polyurethane acrylic resin, polysilazane, and polysiloxane as film-forming resins, and achieves rapid curing by UV, which greatly improves production efficiency; polysilazane has excellent compatibility with aliphatic polyurethane acrylic matrix, and forms a dense coating after curing and enhances the coating strength.

[0046] (3) In this invention, the phosphoric acid modified methacrylic acid oligomer provides high adhesion, transparency and flexibility, while the toughening effects of MQ resin, methylphenyl silicone resin and polysiloxane ensure that the coating maintains long-term mechanical toughness and stability. Polysilazane enhances the strength of the carbon layer while maintaining the mechanical rigidity and weather resistance of the coating. Detailed Implementation

[0047] The present invention will be further illustrated below with reference to specific embodiments. It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of the invention. Furthermore, it should be understood that after reading the teachings of this invention, those skilled in the art can make various alterations or modifications to the invention, and these equivalent forms also fall within the scope defined by the appended claims.

[0048] The following embodiment provides a method for preparing a flame-retardant coating on the backsheet of a lightweight photovoltaic module, comprising the following steps: The components are mixed according to the formula and stirred at room temperature to obtain a coating; then it is applied to the back sheet of a lightweight photovoltaic module and cured to obtain a flame-retardant coating for the back sheet of a lightweight photovoltaic module. Example

[0049] The flame-retardant coating resin formulation consists of bifunctional aliphatic polyurethane acrylate (10 parts), RAYLOLK 1722 (2.8 parts), ammonium polyphosphate (5 parts), pentaerythritol (2 parts), melamine (3 parts), Andisil SF1421 (5 parts), ZG-109 (5 parts), Andisil SF 1230 (5 parts), CF®90-7 (5 parts), AEROXIDE® TiO2 P 25 (20 parts), DM95-G750 (19 parts), DCF-8 (15 parts), TPO (1 part), Trigonox 21S (1 part), UV400 (0.5 parts), BYK333 (0.5 parts), and TP-10H (0.2 parts), with ethyl acetate as the solvent.

[0050] Example 2

[0051] Except for adjusting the proportion of bifunctional aliphatic polyurethane acrylate to 7.5 parts and AEROXIDE® TiO2 P 25 to 22.5 parts in Example 1, the rest is the same as in Example 1.

[0052] Example 3

[0053] Except for adjusting the proportion of bifunctional aliphatic polyurethane acrylate to 5 parts and AEROXIDE® TiO2 P 25 to 25 parts in Example 1, the rest is the same as in Example 1.

[0054] Example 4

[0055] Except for adjusting RAYLOLK 1722 to 1 part and Andisil SF1421 to 7 parts in Example 1, the rest is the same as in Example 1.

[0056] Example 5

[0057] Except for adjusting RAYLOLK 1722 to 1 part and ZG-109 to 7 parts in Example 1, the rest is the same as in Example 1.

[0058] Example 6

[0059] Except for adjusting RAYLOLK 1722 to 1 part and Andisil SF 1230 to 7 parts in Example 1, the rest is the same as in Example 1.

[0060] Example 7

[0061] Except for adjusting RAYLOLK 1722 to 1 part and CF®90-7 to 7 parts in Example 1, everything else is the same as in Example 1.

[0062] Example 8

[0063] Except for adjusting the amount of AEROXIDE® TiO2 P 25 to 24 parts and the amount of DM95-G750 to 15 parts in Example 1, the rest is the same as in Example 1.

[0064] Example 9

[0065] Except for adjusting DM95-G750 to 24 parts and AEROXIDE® TiO2 P 25 to 15 parts in Example 1, the rest is the same as in Example 1.

[0066] Example 10

[0067] Except for replacing RAYLOLK 1722 with GA 2600Y in Example 1, everything else is the same as in Example 1.

[0068] Example 11

[0069] Except for replacing Andisil SF1421 with Andisil SF 4546 in Example 1, everything else is the same as in Example 1.

[0070] Example 12

[0071] Except for replacing ZG-109 in Example 1 with IOTA OPSZ 9150K, everything else is the same as in Example 1.

[0072] Example 13

[0073] Except for replacing ZG-109 with IOTA ST6 in Example 1, everything else is the same as in Example 1.

[0074] Example 14

[0075] Except for replacing Andisil SF 1230 in Example 1 with SICO-P112, everything else is the same as in Example 1.

[0076] Example 15

[0077] Except for replacing CF®90-7 with Andisil MQOH 7 in Example 1, the rest is the same as in Example 1.

[0078] Example 16

[0079] Except for replacing CF®90-7 in Example 1 with Andisil VQM 2050, everything else is the same as in Example 1.

[0080] Example 17

[0081] Except for replacing AEROXIDE® TiO2 P 25 with AEROXIDE® TiO2 P 90 in Example 1, everything else is the same as in Example 1.

[0082] Example 18

[0083] Except for replacing DM95-G750 with W 410 in Example 1, everything else is the same as in Example 1.

[0084] Example 19

[0085] Except for replacing DM95-G750 with W 610 in Example 1, the rest is the same as in Example 1.

[0086] Example 20

[0087] Except for replacing TPO with 184 and Trigonox 21S with BPO in Example 1, the rest is the same as in Example 1.

[0088] Example 21

[0089] Except for replacing the solvent ethyl acetate in Example 1 with butyl acetate, the rest is the same as in Example 1.

[0090] Comparative Example 1 The resin formulation was based on Example 1, except that the phosphoric acid modified methacrylic acid oligomer (RAYLOLK 1722) and the intumescent flame retardant (ammonium polyphosphate, pentaerythritol, melamine) were removed. All other components and their amounts were the same as in Example 1, and the solvent was ethyl acetate.

[0091] Comparative Example 2 The resin formulation was based on Example 1, except that silicon- and nitrogen-containing structural raw materials (Andisil SF1421, ZG-109, Andisil SF 1230, CF®90-7) were removed. All other components and their amounts were the same as in Example 1, and the solvent was ethyl acetate.

[0092] Comparative Example 3 The resin formulation was based on Example 1, except that hollow titanium dioxide (AEROXIDE® TiO2 P 25) and hollow ceramic microspheres (DM95-G750) were removed. All other components and their amounts remained the same as in Example 1, and the solvent was ethyl acetate.

[0093] Comparative Example 4 The resin formulation was based on Example 1, except that the silicate ceramic sintering agent (DCF-8) was removed. All other components and their amounts were the same as in Example 1, and the solvent was ethyl acetate.

[0094] The test methods for flame-retardant coating performance of the examples and comparative examples are shown below:

[0095] Abrasion resistance ASTM D968;

[0096] Coating adhesion ISO 2409;

[0097] DH test: IEC 61215-2-2021, the DH test is the number of aging test hours under 85℃ and 85% ambient humidity conditions;

[0098] Oxygen index: ISO 4589;

[0099] Vertical burning: UL-94;

[0100] Ignition test: GB / T 5169.17-2017, 500W flame, inner flame 40mm, total flame length 125mm, distance 2cm, duration 3min.

[0101] Table 1. Test results of flame retardant coating

[0102] Serial No. Oxygen Index (LOI) Wear Resistance / Coating Adhesion (0-5 scale) UL-94 Vertical Burning Rating Ignition Test DH3000 Post-Oxygen Index (LOI) DH3000 Post-Wear Resistance / Coating Adhesion (0-5 scale) DH3000 Post-UL-94 Vertical Burning Rating DH3000 Post-Ignition Test Comparative Example 1 32.5 1 V-1 Substrate forms char layer, burns through, self-extinguishes 27.8 3 V-2 Substrate forms char layer, burns through, does not self-extinguish Comparative Example 2 33.5 3 V-1 Substrate forms char layer, burns through, self-extinguishes 25.4 5 V-2 Substrate forms char layer, burns through, does not self-extinguish Comparative Example 3 34.5 1 V-1 Substrate forms char layer, burns through, self-extinguishes 21.5 3 V-2 Substrate forms char layer, burns through, does not self-extinguish Comparative Example 4 32.0 1 V-0 Substrate forms char layer, burns through, self-extinguishes 25.5 3 V-2 Substrate forms char layer, burns through, does not self-extinguish Example 1 41.3 0 V-0 Substrate forms char layer, does not burn through, self-extinguishes 38.9 0 V-0 Substrate forms char layer, does not burn through, self-extinguishes Example 2 39.5 0 V-0 Substrate forms char layer, does not burn through, self-extinguishes 37.8 0 V-0 Substrate forms char layer, does not burn through, self-extinguishes Example 3 37.2 0 V-0 Substrate forms char layer, does not burn through, self-extinguishes 36.2 0 V-0 Substrate forms char layer, does not burn through, self-extinguishes Example 4 36.3 0 V-0 Substrate forms char layer, does not burn through, self-extinguishes 35.5 0 V-0 Substrate forms char layer, does not burn through, self-extinguishes Example 5 34.5 0 V-0 Substrate forms char layer, does not burn through, self-extinguishes 33.4 0 V-0 Substrate forms char layer, does not burn through, self-extinguishes Example 6 33.9 0 V-0 Substrate forms char layer, does not burn through, self-extinguishes 32.5 0 V-0 Substrate forms char layer, does not burn through, self-extinguishes Example 7 40.2 0 V-0 Substrate forms char layer, does not burn through, self-extinguishes 37.3 0 V-0 Substrate forms char layer, does not burn through, self-extinguishes Example 8 37.4 0 V-0 Substrate forms char layer, does not burn through, self-extinguishes 35.6 0 V-0 Substrate forms char layer, does not burn through, self-extinguishes Example 9 38.4 0 V-0 Substrate forms char layer, does not burn through, self-extinguishes 36.2 0 V-0 Substrate forms char layer, does not burn through, self-extinguishes Example 10 37.2 0 V-0 Substrate forms char layer, does not burn through, self-extinguishes 36.2 0 V-0 Substrate forms char layer, does not burn through, self-extinguishes Example 11 33.5 0 V-0 Substrate forms char layer, does not burn through, self-extinguishes 32.1 0 V-0 Substrate forms char layer, does not burn through, self-extinguishes Example 12 36.5 0 V-0 Substrate forms char layer, does not burn through, self-extinguishes 34.8 0 V-0 Substrate forms char layer, does not burn through, self-extinguishes Example 13 35.8 0 V-0 Substrate forms char layer, does not burn through, self-extinguishes 33.8 0 V-0 Substrate forms char layer, does not burn through, self-extinguishes Example 14 34.5 0 V-0 Substrate forms char layer, does not burn through, self-extinguishes 32.9 0 V-0 Substrate forms char layer, does not burn through, self-extinguishes Example 15 39.9 0 V-0 Substrate forms char layer, does not burn through, self-extinguishes 37.9 0 V-0 Substrate forms char layer, does not burn through, self-extinguishes Example 16 34.7 0 V-0 Substrate forms char layer, does not burn through, self-extinguishes 33.5 0 V-0 Substrate forms char layer, does not burn through, self-extinguishes Example 17 37.5 0 V-0 Substrate forms char layer, does not burn through, self-extinguishes 36.5 0 V-0 Substrate forms char layer, does not burn through, self-extinguishes Example 18 36.2 0 V-0 Substrate forms char layer, does not burn through, self-extinguishes 35.4 0 V-0 Substrate forms char layer, does not burn through, self-extinguishes Example 19 36.8 0 V-0 Substrate forms char layer, does not burn through, self-extinguishes 34.7 0 V-0 Substrate forms char layer, does not burn through, self-extinguishes Example 20 35.6 0 V-0 Substrate forms char layer, does not burn through, self-extinguishes 34.6 0 V-0 Substrate forms char layer, does not burn through, self-extinguishes Example 21 37.7 0 V-0 Substrate forms char layer, does not burn through, self-extinguishes 36.3 0 V-0 Substrate forms char layer, does not burn through, self-extinguishes

[0103] As shown in the table above, the organic-inorganic flame-retardant coatings for the lightweight photovoltaic module backsheets prepared in Examples 1-25 maintained stable performance after rigorous flame-retardant and ignition tests, and the substrate was not burned through. They formed a variety of synergistic flame retardants, such as expansion-ceramic synergy, phosphorus-silicon synergy, and silicon-silicon synergy, enabling the coating to achieve high flame retardancy, high carbonization residue, high heat insulation, and excellent mechanical properties.

[0104] Comparative Examples 1-4 are coatings prepared by removing some flame-retardant components. Comparative Example 1 is the coating prepared by removing phosphoric acid modified methacrylic acid oligomer and intumescent flame retardant; Comparative Example 2 is the coating prepared by removing silicon and nitrogen-containing structures; Comparative Example 3 is the coating prepared by removing hollow titanium dioxide and hollow ceramic microspheres; and Comparative Example 4 is the coating prepared by removing silicate ceramic sintering agent. As can be seen from the table, the absence of a single component makes it impossible to form multiple synergistic flame retardants such as intumescent-ceramic synergy, phosphorus-silicon synergy, and silicon-silicon synergy. Although the coating has flame retardancy, it suffers from problems such as reduced strength after aging, coating failure, and substrate burn-through.

[0105] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from the spirit or essential characteristics of the invention. Therefore, the embodiments should be considered in all respects as exemplary and non-limiting, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, it is intended that all variations falling within the meaning and scope of equivalents of the claims be included within the present invention.

[0106] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A flame-retardant coating for a lightweight photovoltaic module backsheet, characterized in that, By mass, its raw materials include the following components: 5-10 parts of aliphatic polyurethane acrylate; 1-3 parts of phosphoric acid modified methacrylic acid oligomer; 10-15 parts of intumescent flame retardant; 5-10 parts of polysiloxane; 5-10 parts of polysilazane; 5-10 parts of methylphenyl silicone resin; 5-10 parts of MQ resin; 15-25 parts of hollow titanium dioxide; 15-25 parts of hollow ceramic microspheres; 15-30 parts of silicate ceramic sintering agent; 1-3 parts of curing agent; 0.5-2 parts of ultraviolet absorber; 0.2-0.5 parts of leveling and wetting agent; Antioxidant 0.2-0.5 parts; And solvents that account for 30%-40% of the total mass fraction of the raw materials.

2. The flame-retardant coating for the backsheet of a lightweight photovoltaic module according to claim 1, characterized in that, The phosphoric acid modified methacrylic acid oligomer is one or more of RAYLOLK 1722 and GA 2600Y.

3. The flame-retardant coating for the backsheet of a lightweight photovoltaic module according to claim 1, characterized in that, The intumescent flame retardant is a mixture of ammonium polyphosphate, pentaerythritol, and melamine.

4. The flame-retardant coating for the backsheet of a lightweight photovoltaic module according to claim 1, characterized in that, The polysiloxane is one or more of Andisil SF1421 and Andisil SF 4546; the polysilazane is one or more of ZG-109, ZG-UV678, IOTA OPSZ 9150K, and IOTA ST6; the methylphenyl silicone resin is one or more of Andisil SF 1230, SICO-P112, and SICO-P212; and the MQ resin is CF ® One or more of Andisil MQOH 7, Andisil VQM 1, Andisil VQM 2050, and Andisil VQM 1040.

5. The flame-retardant coating for the backsheet of a lightweight photovoltaic module according to claim 1, characterized in that, The hollow titanium dioxide is one or more of AEROXIDE® TiO2 P 25, AEROXIDE® TiO2 P 90, and Photospheres™; the hollow ceramic microspheres are one or more of DM95-G750, W210, W410, and W610; and the silicate ceramic sintering agent is one or more of DCF-8 and DCF-1.

6. The flame-retardant coating for the backsheet of a lightweight photovoltaic module according to claim 1, characterized in that, The curing agent is one or more of TPO, 184, 1173, 819, P16, Trigonox 21S, BPO, and Trigonox C.

7. The flame-retardant coating for the backsheet of a lightweight photovoltaic module according to claim 1, characterized in that, The ultraviolet absorber is one or more of UV400, UV1164, UV329, and UV1130; the leveling and wetting agent is one or more of BYK333, Tego2100, Tego4100, WET 240, WET 270, and BYK3510; and the antioxidant is one or more of TP-10H, 323TP, 1010, 168, Irganox® B900, and ADEKA PEP-36.

8. The flame-retardant coating for the backsheet of a lightweight photovoltaic module according to claim 1, characterized in that, The solvent is one or more of ethyl acetate, acetone, and butyl acetate.

9. A method for preparing a flame-retardant coating for a lightweight photovoltaic module backsheet as described in any one of claims 1 to 8, characterized in that, Includes the following steps: The components are mixed according to the formula and stirred at room temperature to obtain a coating; then it is applied to the back sheet of a lightweight photovoltaic module and cured to obtain a flame-retardant coating for the back sheet of a lightweight photovoltaic module.

10. The preparation method according to claim 9, characterized in that, The lightweight photovoltaic module backsheet is one or more of CPC, PP-FRP, and fiberglass composite materials.