Common ingredients: silicone adhesives and sealants

Representative Manufacturers


Used in Product Categories: Resilient Flooring Adhesive Components, Wood Flooring Adhesive Components, Roofing Membrane Adhesive Components, Resilient Flooring Adhesives, Wood Flooring Adhesives, Roofing Membrane Adhesives, Resilient Flooring, Adhesives, Flooring, High Performance Coatings, High Performance Coating Components

Content status: Sufficient Content Record

Description:

The term "silicones" is "generally applied to ‘polymeric siloxane products, usually complex, often undefinable in exact scientific terms, frequently mixtures of many components, and in many cases useful in one or more practical ways.…. The commercial silicones are extremely complex polymer mixtures. These fluids normally consist of long, straight-chain polydimethylsiloxanes…. A common fluid is polydimethylsiloxane with a small percentage of methylphenyl substituted groups evenly distributed throughout the polymer chain." (EPA 1974)

Silicone-based adhesives are used in a vast number of products within the construction, automotive, aviation and marine industries where they must hold crucial systems together under considerable stress. Products from these industries benefit from the ability of silicone-based adhesives to enhance weatherability and perform in wet and dry conditions.  (European Silicones Centre)

Composition of adhesives and sealants

"Silicone adhesives and silicone sealants are typically supplied as one-part systems that range in viscosity from self-leveling liquids to non-slumping pastes....  During crosslinking, a by-product is released. Depending on the cure chemistry, it can be acidic (e.g., acetic acid), basic (e.g., amine) or neutral (e.g., oxime or alcohol).... Selecting the right curing system (Crosslinker) is key to determining the properties of the silicone adhesive."  (Chenso)

"Typical one-component room temperature vulanizing (RTV) silicone sealants consist of the following components:

60-80% siloxane; 5-7% cross-linking agent (tri- or tetrafunctional silanes);  20-30% CaCo2 filler; 1-6% silica filler; 5-20% drying agents (siccatives);  0.05-0.1% organotin catalyst” (Denmark)

Siloxanes

"Siloxanes are basic members of the silicone family, serving as the building blocks for many silicones." (European Silicones Centre)

"In colloquial language the term silicones is often used synonymously with siloxanes....  The properties of the siloxanes and the silicone products depend on the length of the Si-O backbone, the chemical groups attached to the backbone and the presence of cross-links between the backbones. Silicone products are grouped into silicone fluids, elastomers and resins. Silicone fluids are used for a wide range of applications, silicone elastomers are mainly used for sealants and rubbers, and resins are mainly used for paints. The most common siloxanes are polydimethylsiloxane (PDMS) with different modifications.” (Danish study)

Cross-linking agents (silanes)

"Silanes are used as precursors in the production of siloxanes and are used as cross-linking agents for formation of silicone elastomers and resins.  (Danish study)

"Silanes are a family of speciality products, mostly liquids, also based on silicon and closely related to silicones." (European Silicones Centre)

Catalysts

Dibutyltin dilaurate is the primary "catalyst for the curing of room-temperature-vulcanized (RTV) silicone elastomers to produce flexible silicone rubbers used as sealing compounds, insulators, and in a wide variety of other applications.” [Kirk-Othmer Encyclopedia of Chemical Technology. 4th ed. Volumes 1: New York, NY. John Wiley and Sons, 1991-Present., p. V24 145 (1997)]

Pharos Team Notes:

Two chemicals commonly used in silicone adhesives and sealants raise environmental and human health issues.

Octamethylcyclotetrasiloxane (D4) is a siloxane commonly used in these compositions. It is under increasing regulatory scrutiny.  

The state of Oregon classifies D4 as a persistent, bioaccumulative, toxicant.  It has determined that it is a "Tier 1" PBT and notes that indicates that “Canada, with an approach similar to DEQ’s, has concluded that this chemical is “P” and “T”, while “B” is equivocal (but possibly >1000)."

A state of California study notes, "Cyclosiloxanes appear to be persistent and to have long half-lives in people. The weak estrogenic activity of D4, in combination with its long half-life, poses potential concerns for exposed individuals."  

And the Danish EPA reports that,  "D4 is on the list of potential PBT and vPvB (very persistent and very bioaccumulative) substances selected on the basis of screening criteria in the EU (DEPA 2003)

Organotin catalysts typically associated with silicone adhesives and sealants used in construction are also classified as a PBT by the Oslo-Paris Commission.   In addition to this ecological hazard, organotin catalysts may be subject to conflict rules reporting by the Securities and Exchange Commission.

 

Direct Content Hazards:

PBT EC - CEPA DSL - Persistent, Bioaccumulative and inherently Toxic (PBiTE) to the Environment (based on aquatic organisms) - from Octamethylcyclotetrasiloxane (D4) + 5
DEVELOPMENTAL MAK - Pregnancy Risk Group B - from Dibutyltin compounds
REPRODUCTIVE EU - Annex VI CMRs - Reproductive Toxicity - Category 1B - from Dibutyltin dilaurate + 10
BIOACCUMULATIVE EC - CEPA DSL - Bioaccumulative - from Octamethylcyclotetrasiloxane (D4) + 2
PERSISTENT EC - CEPA DSL - Persistent - from ETHYLSILANETRIOL TRIACETATE + 1
CANCER MAK - Carcinogen Group 4 - Non-genotoxic carcinogen with low risk under MAK/BAT levels - from Dibutyltin compounds
ENDOCRINE ChemSec - SIN List - Endocrine Disruption - from Dibutyltin dilaurate + 2
GENE MUTATION EU - GHS (H-Statements) - H341 - Suspected of causing genetic defects - from Dibutyltin dilaurate + 2
MAMMALIAN Australia - GHS - H330 - Fatal if inhaled - from Dibutyltin dilaurate + 14
EYE IRRITATION Japan - GHS - Serious eye damage / eye irritation - Category 1 - from ETHYLSILANETRIOL TRIACETATE + 5
SKIN IRRITATION Australia - GHS - H314 - Causes severe skin burns and eye damage - from Dibutyltin dilaurate + 7
ORGAN TOXICANT EU - GHS (H-Statements) - H372 - Causes damage to organs through prolonged or repeated exposure - from Dibutyltin dilaurate + 8
ACUTE AQUATIC Japan - GHS - Hazardous to the aquatic environment (acute) - Category 1 - from Dibutyltin dilaurate + 4
TERRESTRIAL New Zealand - GHS - 9.3A - Very ecotoxic to terrestrial vertebrates - from Dibutyltin dilaurate + 2
CHRON AQUATIC Australia - GHS - H413 - May cause long lasting harmful effects to aquatic life - from Octamethylcyclotetrasiloxane (D4) + 8
FLAMMABLE Japan - GHS - Flammable liquids - Category 3 - from Octamethylcyclotetrasiloxane (D4) + 2
REACTIVE Québec CSST - WHMIS 1988 - Class E - Corrosive materials - from METHYLSILANETRIOL TRIACETATE
RESTRICTED LIST US EPA - DfE SCIL - Yellow Triangle - best available in class but some hazard profile issues - from Polydimethylsiloxanes + 17
MULTIPLE Québec CSST - WHMIS 1988 - Class D2B - Toxic material causing other toxic effects - from Dibutyltin dilaurate + 8
RESPIRATORY EU - Manufacturer REACH hazard submissions - H334 - May cause allergy or asthma symptoms or breathing difficulties if inhaled (unverified) - from Dibutyltin dilaurate
SKIN SENSITIZE EU - Manufacturer REACH hazard submissions - H317 - May cause an allergic skin reaction (unverified) - from Dibutyltin dilaurate
EXEMPT US EPA - Exempt VOCs - Non-smog forming exempt VOCs - from Volatile Methylated Siloxanes (VMS)
POSITIVE LIST US EPA - DfE SCIL - Green Half-Circle - Expected Low Concern - from Siloxanes and Silicones, di-Me, hydroxy-terminated

Potential Residual Hazards:

See Process Chemistry Research tab for details on residuals and other substances used in manufacture.

PBT ChemSec - SIN List - PBT / vPvB (Persistent, Bioaccumulative, & Toxic / very Persistent & very Bioaccumulative) - from DECAMETHYLCYCLOPENTASILOXANE (D5) + 6
BIOACCUMULATIVE EC - CEPA DSL - Bioaccumulative - from DECAMETHYLCYCLOPENTASILOXANE (D5) + 2
PERSISTENT EC - CEPA DSL - Persistent - from DECAMETHYLCYCLOPENTASILOXANE (D5) + 1
DEVELOPMENTAL MAK - Pregnancy Risk Group C - from ACETIC ACID, GLACIAL
REPRODUCTIVE EU - Annex VI CMRs - Reproductive Toxicity - Category 2 - from Octamethylcyclotetrasiloxane (D4) + 5
ENDOCRINE ChemSec - SIN List - Endocrine Disruption - from Octamethylcyclotetrasiloxane (D4) + 2
RESPIRATORY AOEC - Asthmagens - Asthmagen (Rr&Rs) - irritant-induced & sensitizer-induced - from ACETIC ACID, GLACIAL + 1
EYE IRRITATION Japan - GHS - Serious eye damage / eye irritation - Category 1 - from ACETIC ACID, GLACIAL + 4
SKIN IRRITATION EU - GHS (H-Statements) - H314 - Causes severe skin burns and eye damage - from ACETIC ACID, GLACIAL + 6
ORGAN TOXICANT Japan - GHS - Specific target organs/systemic toxicity following single exposure - Category 1 - from ACETIC ACID, GLACIAL + 3
TERRESTRIAL New Zealand - GHS - 9.4A - Very ecotoxic to terrestrial invertebrates - from Polydimethylsiloxanes + 1
MAMMALIAN Japan - GHS - Acute toxicity (dermal) - Category 4 - from ACETIC ACID, GLACIAL + 10
ACUTE AQUATIC Japan - GHS - Hazardous to the aquatic environment (acute) - Category 3 - from ACETIC ACID, GLACIAL + 3
CHRON AQUATIC Australia - GHS - H413 - May cause long lasting harmful effects to aquatic life - from Octamethylcyclotetrasiloxane (D4) + 5
FLAMMABLE EU - GHS (H-Statements) - H226 - Flammable liquid and vapour - from ACETIC ACID, GLACIAL + 8
REACTIVE New Zealand - GHS - 8.1A - Corrosive to metals - from ACETIC ACID, GLACIAL + 2
RESTRICTED LIST US EPA - DfE SCIL - Yellow Triangle - best available in class but some hazard profile issues - from Polydimethylsiloxanes + 9
NEUROTOXICITY Boyes - Neurotoxicants - Neurotoxic - from ACETIC ACID, GLACIAL
MULTIPLE ChemSec - SIN List - CMR - Carcinogen, Mutagen &/or Reproductive Toxicant - from DECAMETHYLCYCLOPENTASILOXANE (D5) + 6
POSITIVE LIST US EPA - DfE SCIL - Green Circle - Verified Low Concern - from ACETIC ACID, GLACIAL

Common Contents:

Material % Wt. Part % Wt. Whole Hazard GreenScreen Renewable
Substance Residual Manufacturing
[70131-67-8] Siloxanes and Silicones, di-Me, hydroxy-terminated 60.00 - 90.00 % 60.00 - 90.00 %       2
[68611-44-9] SILANE, DICHLORODIMETHYL-, REACTION PRODUCTS WITH SILICA 10.00 - 30.00 % 10.00 - 30.00 %       LT-UNK
[63148-62-9] Polydimethylsiloxanes 3.00 - 40.00 % 3.00 - 40.00 %       LT-P1
[2530-83-8] ((3-(TRIMETHOXYSILYL)PROPOXY)METHYL)OXIRANE 1.00 - 10.00 % 1.00 - 10.00 %   LT-P1
[556-67-2] Octamethylcyclotetrasiloxane (D4) 1.00 - 5.00 % 1.00 - 5.00 %     1
[17689-77-9] ETHYLSILANETRIOL TRIACETATE 1.00 - 5.00 % 1.00 - 5.00 %     LT-P1
[4253-34-3] METHYLSILANETRIOL TRIACETATE 1.00 - 5.00 % 1.00 - 5.00 %     LT-UNK
[77-58-7] Dibutyltin dilaurate 0.10 % 0.10 %   LT-1

Process Chemistry - Known or Potential Residuals:

Material Hazard Type Frequency % Wt. Part % Wt. Whole Notes
Substance Residual Manufacturing
[64-19-7] ACETIC ACID, GLACIAL - from ETHYLSILANETRIOL TRIACETATE     Pollutant/ Contaminant Occasional/Rare (known) 5.00 % Unknown
[64-19-7] ACETIC ACID, GLACIAL - from METHYLSILANETRIOL TRIACETATE     Pollutant/ Contaminant Occasional/Rare (known) 3.00 % Unknown
[541-02-6] DECAMETHYLCYCLOPENTASILOXANE (D5) - from Polydimethylsiloxanes     Reactant Frequent (known) Unknown Unknown
[556-67-2] Octamethylcyclotetrasiloxane (D4) - from Siloxanes and Silicones, di-Me, hydroxy-terminated     Pollutant/ Contaminant Frequent (known) Unknown Unknown
[63148-62-9] Polydimethylsiloxanes - from SILANE, DICHLORODIMETHYL-, REACTION PRODUCTS WITH SILICA       Reactant Integral (known) Unknown Unknown
[541-02-6] DECAMETHYLCYCLOPENTASILOXANE (D5)     Reactant Frequent (known) Unknown Unknown

Process Chemistry - Other:

Material Hazard Type Frequency % Wt. Part % Wt. Whole Notes
Substance Residual Manufacturing
[75-78-5] DICHLORODIMETHYLSILANE - from Octamethylcyclotetrasiloxane (D4)   Reactant Integral Unknown Unknown
[75-78-5] DICHLORODIMETHYLSILANE - from SILANE, DICHLORODIMETHYL-, REACTION PRODUCTS WITH SILICA   Reactant Integral Unknown Unknown
[7631-86-9] SILICA, AMORPHOUS - from SILANE, DICHLORODIMETHYL-, REACTION PRODUCTS WITH SILICA     Reactant Integral Unknown Unknown

No VOC content data provided

GreenScreen for Safer Chemicals Full Assessment: None available

Highest concern GreenScreen score : Benchmark 1

Cradle to Cradle Certified™ List Hazards

What are C2C hazards and what do these colors mean?

How to Use These Scores in a C2C Assessment

Acute and Chronic Tox. Acute Aquatic Tox. Chronic Aquatic Tox.
C M R+D E O D I O/D/I N IrS+IrE SnS+SnR Fish Inv. Alg. Any Fish Inv. Alg. Any T P B Climate Organohalogen Toxic Metal Other Mult
Y R R R/Y R ? R R - R - ? ? - R - ? ? R ? R/Y R G NL R Y R

Full Hazard List By Endpoint:

Carcinogenicity MAK - Carcinogen Group 4 - Non-genotoxic carcinogen with low risk under MAK/BAT levels: Yellow
Mutagenicity Australia - GHS - H341 - Suspected of causing genetic defects: Red
EU - GHS (H-Statements) - H341 - Suspected of causing genetic defects: Red
Reproductive Toxicity (Repro + Dev) Australia - GHS - H360Fd - May damage fertility. Suspected of damaging the unborn child: Red
EU - REACH Annex XVII CMRs - Toxic to Reproduction Category 2 - Substances which should be regarded as if they impair fertility or cause Developmental Toxicity in humans: Red
Japan - GHS - Toxic to reproduction - Category 1B: Red
MAK - Pregnancy Risk Group B: Red
Australia - GHS - H361f - Suspected of damaging fertility: Red
EU - GHS (H-Statements) - H361f - Suspected of damaging fertility: Red
Japan - GHS - Toxic to reproduction - Category 2: Red
New Zealand - GHS - 6.8B - Suspected human reproductive or developmental toxicants: Not rated
US EPA - PPT Chemical Action Plans - Reproductive toxicity - TSCA Criteria met: Not rated
Endocrine Disruption ChemSec - SIN List - Endocrine Disruption: Red or Yellow
EU - Priority Endocrine Disruptors - Category 1 - In vivo evidence of Endocrine Disruption Activity: Red or Yellow
TEDX - Potential Endocrine Disruptors - Potential Endocrine Disruptor: Red or Yellow
Oral Toxicity Japan - GHS - Acute toxicity (oral) - Category 3: Red
New Zealand - GHS - 6.1B (oral) - Acutely toxic: Not rated
New Zealand - GHS - 6.9A (oral) - Toxic to human target organs or systems (Cat. 1): Not rated
New Zealand - GHS - 6.9B (oral) - Harmful to human target organs or systems (Cat. 2): Not rated
Japan - GHS - Acute toxicity (oral) - Category 4: Yellow
New Zealand - GHS - 6.1D (oral) - Acutely toxic: Not rated
Dermal Toxicity New Zealand - GHS - 6.1C (dermal) - Acutely toxic: Not rated
New Zealand - GHS - 6.1D (dermal) - Acutely toxic: Not rated
Inhalative Toxicity Australia - GHS - H330 - Fatal if inhaled: Red
Japan - GHS - Acute toxicity (inhalation: dust, mist) - Category 2: Red
New Zealand - GHS - 6.1B (inhalation) - Acutely toxic: Not rated
New Zealand - GHS - 6.1E (inhalation) - Acutely toxic: Not rated
Oral, Dermal, and/or Inhalative Toxicity Australia - GHS - H372 - Causes damage to organs through prolonged or repeated exposure: Red
EU - GHS (H-Statements) - H372 - Causes damage to organs through prolonged or repeated exposure: Red
Japan - GHS - Specific target organs/systemic toxicity following repeated exposure - Category 1: Red
Québec CSST - WHMIS 1988 - Class D1B - Toxic material causing immediate and serious toxic effects: Red or Yellow
Japan - GHS - Specific target organs/systemic toxicity following single exposure - Category 2: Yellow
Neurotoxicity not listed
Skin, Eye, and Respiratory Corrosion/Irritation New Zealand - GHS - 6.3B - Mildly irritating to the skin: Not rated
New Zealand - GHS - 6.4A - Irritating to the eye (Cat. 2A): Not rated
Australia - GHS - H314 - Causes severe skin burns and eye damage: Red
Japan - GHS - Serious eye damage / eye irritation - Category 2A: Yellow
Japan - GHS - Skin corrosion / irritation - Category 2: Yellow
New Zealand - GHS - 6.3A - Irritating to the skin (Cat. 2): Not rated
Japan - GHS - Serious eye damage / eye irritation - Category 1: Red
Japan - GHS - Skin corrosion / irritation - Category 1: Red
New Zealand - GHS - 8.2C - Corrosive to dermal tissue (Cat. 1C): Not rated
New Zealand - GHS - 8.3A - Corrosive to ocular tissue (Cat. 1): Not rated
Skin and Respiratory Sensitization not listed
Acute Aquatic Toxicity (Fish) New Zealand - GHS - 9.1A (fish) - Very ecotoxic in the aquatic environment: Not rated
New Zealand - GHS - 9.1C (fish) - Harmful in the aquatic environment: Not rated
Acute Aquatic Toxicity (Invertibrates) New Zealand - GHS - 9.1A (crustacean) - Very ecotoxic in the aquatic environment: Not rated
Acute Aquatic Toxicity (Algae) not listed
Acute Aquatic Toxicity (Fish, Invertibrates, and/or Algae) Japan - GHS - Hazardous to the aquatic environment (acute) - Category 1: Red
Chronic Aquatic Toxicity (Fish) not listed
Chronic Aquatic Toxicity (Invertibrates) New Zealand - GHS - 9.1C (crustacean) - Harmful in the aquatic environment: Not rated
New Zealand - GHS - 9.1D (crustacean) - Slightly harmful in the aquatic environment or are otherwise designed for biocidal action: Not rated
Chronic Aquatic Toxicity (Algae) New Zealand - GHS - 9.1C (algal) - Harmful in the aquatic environment: Not rated
Chronic Aquatic Toxicity (Fish, Invertibrates, and/or Algae) Japan - GHS - Hazardous to the aquatic environment (chronic) - Category 1: Not rated
Australia - GHS - H413 - May cause long lasting harmful effects to aquatic life: Red
EU - GHS (H-Statements) - H413 - May cause long lasting harmful effects to aquatic life: Red
Terrestrial New Zealand - GHS - 9.3A - Very ecotoxic to terrestrial vertebrates: Not rated
New Zealand - GHS - 9.3B - Ecotoxic to terrestrial vertebrates: Not rated
New Zealand - GHS - 9.4A - Very ecotoxic to terrestrial invertebrates: Not rated
Persistence EC - CEPA DSL - Persistent: Red or Yellow
US EPA - PPT Chemical Action Plans - Medium environmental persistence - TSCA Criteria met: Not rated
Bioaccumulation EC - CEPA DSL - Bioaccumulative: Red
US EPA - PPT Chemical Action Plans - High bioaccumulation potential - TSCA Criteria met: Not rated
US EPA - PPT Chemical Action Plans - Moderate bioaccumulation potential - TSCA Criteria met: Not rated
Climatic Relevance not listed
Organohalogen not listed - This chemical is not on the Pharos list of organohalogens, but we may have missed a few. Please double-check the chemical structure to confirm there are no carbon-halogen bonds.
Toxic Metal ORGANOTIN COMPOUNDS
Other (Human Health) Japan - GHS - Flammable liquids - Category 3: Yellow
New Zealand - GHS - 3.1C - Flammable Liquids: medium hazard: Not rated
Multiple Endpoints German FEA - Substances Hazardous to Waters - Class 2 - Hazard to Waters: Red
ChemSec - SIN List - CMR - Carcinogen, Mutagen &/or Reproductive Toxicant: Red
EC - CEPA DSL - Inherently Toxic in the Environment: Red
EU - Annex VI CMRs - Reproductive Toxicity - Category 1B: Red
EU - GHS (H-Statements) - H360FD - May damage fertility. May damage the unborn child: Red
German FEA - Substances Hazardous to Waters - Class 3 - Severe Hazard to Waters: Red
Québec CSST - WHMIS 1988 - Class D2B - Toxic material causing other toxic effects: Red
Québec CSST - WHMIS 1988 - Class E - Corrosive materials: Red
EC - CEPA DSL - Inherently Toxic to Humans (iT human): Red
EC - CEPA DSL - Persistent, Bioaccumulative and inherently Toxic (PBiTE) to the Environment (based on aquatic organisms): Red
EC - CEPA DSL - Persistent, Bioaccumulative and inherently Toxic (PBiTH) to humans: Red
EC - CEPA Toxic Substances (Sched 1) - CEPA Toxics: Red
EU - Annex VI CMRs - Reproductive Toxicity - Category 2: Red
OR DEQ - Priority Persistent Pollutants - Priority Persistent Pollutant - Tier 1: Red
EU - SVHC Authorisation List - PBT - Candidate list: Not rated
EU - SVHC Authorisation List - vPvB - Candidate list: Not rated
German FEA - Substances Hazardous to Waters - Class 1 - Low Hazard to Waters: Red
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  • bostik G.pdf
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