Synthesized Molecule of Solketal Esters from Palm Kit Oil and Glycerin for Cosmetic and Agricultural Formulations

Abstract

It refers to a new group of solketal monoesters having excellent solubility power in sunscreens, excellent emollient properties, spreadability and ease of preparing stable aqueous formulas, completely non-toxic, without characteristics that generate eye or skin irritation, which allows its use as a solubilizer and emollients in cosmetic formulations for body use, facial sunscreens, makeup removers and a component for use in “roll on” deodorants. The proposed molecule is obtained from palm kernel oil, coconut oil, macauba oil and glycerin as a solubilizer in the form of cocoyl solketal ester, more particularly solketal monoester prepared from oils and/or fatty acids of coconut, babassu, palm kernel.

Description

CROSS REFERENCE TO RELATED APPLICATION

The present invention claims the benefit of priority to Brazilian Patent Application No. 10 2023 000441 5 filed on Jan. 10, 2023 with the Brazilian Patent Office, the entire contents of which are incorporated herein by reference in its entirety.

TECHNICAL FIELD

The invention is based on the development of a new molecule based on the solketal ester of palm kernel oil, coconut oil, palm oil, which chemical structure confers a high solubilizing power combined with excellent wetting, emollience, spreadability and softness.

Soluble in oils and non-polar substances with excellent emulsibility power, its composition is entirely based on natural and renewable raw materials.

These properties make these products excellent candidates as components in cosmetic and personal care formulations, such as sunscreens, body creams, antiperspirants and deodorants, and also in agricultural formulations where the same properties are desired by leaves, trunks and roots.

BACKGROUND OF THE INVENTION

The products most used in the applications mentioned above are those that can solubilize solar ultraviolet radiation protection filters such as dibenzoylmethane derivatives, mainly 4-(1,1-dimethylethyl)-4-methoxydibenzoylmethane (PARSOL® 1789) and cinnamic acid derivatives, particularly 2-ethylhexyl paramethoxycinnamate and octylcinnamate, to prepare liquids with a stable composition, good spreadability, non-irritability, resistant to washing and, mainly, liquids that provide a feeling of comfort on human skin.

Esters of benzoic acid made with carbonic chain alcohols from C1 to C18, especially those with a short chain, such as methyl benzoate, are quite common; dicaprylic ethers, fatty acid esters, such as isopropyl myristate, isopropyl palmitate, octyl octoate, esters.

Esters produced from linear or branched carbon chain carboxylic acids containing 8 to 18 carbons and acetals produced from glycerin reacted with ketones or aldehydes are the target end products of the present invention.

Due to the broad variety of existing products, the products are selected in the vast majority of cases based on the performance, cost and availability of the product in each region. Products from renewable sources may, in some applications, have greater added value than those from petrochemical sources.

Formulations are made using more than one product to obtain the desired effects for each specific need, for example, the use of natural antioxidants in cosmetic formulations that use fatty esters as oil-giving agents for the skin. In the industrial field, products and formulations containing lubricity, spreadability, anti-corrosion protection, plasticity, adhesiveness, solvency, hydrophilicity and hydrophobicity effects are highly demanded by the market.

The cosmetic industry, in the production of creams, shampoos, and sunscreens, uses esters of fatty acids, such as octyl stearate, isopropyl palmitate, cetyl palmitate, combined with tocopherols to obtain an oily effect and skin and hair protection.

The domestic and industrial hygiene industry frequently uses glycols such as butyl glycol or its acetate, monoethylene glycol, monoethylene glycol ether, in cleaning formulations such as detergents, soaps, multipurpose cleaners.

In the agricultural industry, the use of ethylhexyl lactate, lactamides, toluol, xylene, methyl caprylate, methyl oleate, methyl linoleate, isoparaffins, triacetin, isophorones, citric acid esters, lactic acid esters, maleic acid diesters, propylene glycol and its diesters, dimethicone, phthalic acid diesters, etc.

Sunscreens and a variety of additives used in cosmetic formulations are solid substances that are difficult to solubilize. Non-toxic products that solubilize and provide good spreadability are the most desired for this type of market. They normally use several components seeking the most balanced formula considering the regions, their different ethnicities, climates, and economic power so that a greater number of users can benefit from a safe and accessible formula.

Document U.S. Pat. No. 5,783,173 describes sunscreens and their stable formulations that use benzoic acid derivatives as a solubilizer and emollient.

Document BR102013010477 describes the development of new benzoic acid esters using branched alcohols which purpose is the formulation of sunscreens, deodorants, antiperspirants.

Document U.S. Pat. No. 7,166,739 B2 also describes new esters for cosmetic purposes.

The objective of the present invention is to create, with glycerin derivatives, motivated by the growing global production of the same, new sunscreen solubilizing agents and agricultural active ingredients since they are the components that are most difficult to solubilize.

OBJECTIVES OF THE INVENTION

It is considered that the global esthetic market is expected to overcome the US$21 billion mark up to 2024, growing at an annual rate of 12.2% during this period, according to the 2018 report from the company Market Research Engine.

This result is due to reasons such as greater awareness among consumers; health benefits of medical esthetic procedures; increase in the elderly population; change in preference from surgical to non-surgical procedures; and advancement in laser technology.

The emollient is a non-greasy oily and lipid compound, which hydrates and restores the oiliness of dry skin. It prevents water evaporation through the formation of an occlusive film, generating the activation of local circulation.

The emollient fills the “spaces” in the skin cells, so the product is easily spread. Humectants, on the other hand, retain around 70% of the water, making it ideal to be used when the skin is damp, so as not to lose moisture easily.

Moisturizers using occlusive agents, in turn, form a layer that slows water loss and leaves the skin looking brighter and stickier.

A desired molecule for the purpose of this patent would have to have the following properties:

• • 1.—high solubilization power.
  • 2.—excellent hydration.
  • 3.—spreadability.
  • 4.—hydration of skin and hair.
  • 5.—formation of a barrier on the skin.
  • 6.—washability resistance.
  • 7.—microbial activity.
  • 8.—chemical and thermal stability.
  • 9.—do not interfere with other active ingredients.
  • 10.—be of natural origin.
  • 11.—biodegradable.
  • 12.—competitive cost.

The objective of the present invention is to create a product to meet the aforementioned requirements of this molecule.

DESCRIPTION OF THE INVENTION

The present invention has as its reference the document BR 10 2013 010477 9 requested by the same applicant which describes the synthesis and applications of acetal esters, which was previously described in patent PI 0603912-0 and PI0703673-6, where the acetals can be formed in situ, that is, acetals and esters are formed at the same time, wherein the glycerin used is the purified glycerin obtained according to patent BR 1020120015846, although distilled glycerin or market standard treated blonde glycerin can be used in the synthesis of the product claimed in the present invention. Acetals in this case are synthesized using aldehydes (from carbons 1 to 8).

The present invention is directed to the use of a specific group of solketal esters for use in personal use formulations. It has been proven that solketal esters containing 12 to 24 total carbons originating from the carbon chain of the carboxylic acid plus the carbons coming from solketals have excellent solubilization power, are not irritating to human skin or eyes, are non-toxic, have excellent chemical and hydrolytic stability, good lubricity, low oiliness, and generate stable emulsions and aqueous dispersions. These are the initial requirements for candidates for the chemical group called solubilizers and emollients in the cosmetic industry.

These esters are represented by the chemical structure below:

• • R1 represents 3 to 8 carbons.
  • R2 represents 8 to 18 carbons.

Table 1 below shows the basic physical and chemical characteristics of cocoyl glyceryl solketal used in solubilization tests and sunscreen formulations:

TABLE 1
(COCOIL GLYCERYL SOLKETAL-LOT HNC214).
Aspect                         Transparent liquid
Active substance               99.8%
odor                           characteristic
Freezing point (Celsius)       −3° C.
Flash point (Celsius)          155
Density at 25° C.              0.925
viscosity @ 40 Celsius         8.2 centistokes
Acid value (mgkoh/g)           0.2
Saponification index (mgkoh/g) 178
Color Gardner                  <1

Table 2 below shows the solubility of 3 commercially available sunscreens using cocoyl glyceryl acetal as a solubilizing agent.

TABLE 2
SOLUBILITY OF 3 SOLAR FILTERS.
                              Solubility at 25° C. grams/
                              100 grams of cocoyl
Name of sun protection filter glyceryl solketal
Ethylhexyl Triazone           16.0
Diethylamino hydroxybenzoyl   18.0
hexyl benzoate
4-(1,1-dimethylethyl)-4-      14.0
methoxydibenzoylmethane

In oral and acute toxicity tests, the product was classified as class 5 (non-toxic) according to GHS standards—globally harmonized classification for chemical substances and mixtures.

In eye irritation tests, the product was classified as non-irritating according to OECD and GHS standards.

In skin irritation tests, the product was classified as non-irritating in 2 tests according to OECD and GHS standards, wherein one of the tests shows mild dermal irritation.

Two new batches of cocoyl glyceryl solketal were sent to confirm dermal irritation tests.

In the following examples, the substance proposed in the invention, Cocoyl glyceryl solketal was tested in formulations of ultraviolet radiation protective body lotion (example 1), oil-free facial sunscreen (example 2), makeup remover (example 3) and antiperspirant deodorant formulation (example 4), all being compared with products commercially used on the market: C12-C15 Alkyl Benzoate, Dibutyl adipate, dicaprylyl carbonate.

EXAMPLE 1

TABLE 3
BODY LOTION SPF 30
Phase	Composition-INCI names	Test A	Test B	Test C	Test D
I	Xanthan Gum	0.10	0.10	0.10	0.10
I	Glycerin	1.00	1.00	1.00	1.00
II	Disodium EDTA	0.05	0.05	0.05	0.05
II	Acrylates/Beheneth-25	0.50	0.50	0.50	0.50
	Methacrylate Copolymer
II	Water	100	100	100	100
III	Diethylamino Hydroxybenzoyl	5.50	5.50	5.50	5.50
	Hexyl Benzoate
III	Titanium Dioxide (and)	2.00	2.00	2.00	2.00
	Hydrated Silica (and)
	Dimethicon/Methicone
	Copolymer (and) Aluminum
	Hydroxide.
III	Ethylhexyl Methoxycinnamate		9.00	9.00	9.00
III	Cocoyl Glyceryl Solketal	3.00	—	—	—
III	C12-C15 Alkyl Benzoate	—	3.00	—	—
III	Dibutyl Adipate	—	—	3.00	—
III	Dicaprylyl Carbonate	—			3.00
III	Caprylic Capric Triglyceride	3.00	3.00	3.00	3.00
III	Cetearyl Alcohol	2.00	2.00	2.00	2.00
III	Glyceryl Stearate	2.00	2.00	2.00	2.00
III	Sodium Cetearyl Sulfate	2.00	2.00	2.00	2.00
III	BHT	0.10	0.10	0.10	0.10
IV	Aminomethyl Propanol	qs	qs	qs	qs
V	Methylene Bis Benzotriazolyl	0.30	0.30	0.30	0.30
	Tetramethylbutylpheno, aqua,
	Decylglucoside, Propylene
	Glycol, Xanthan Gum.
V	Aqua	0.30	0.30	0.30	0.30
VI	Phenoxyethanol (and)	0.50	0.50	0.50	0.50
	Methylparaben (and)
	Ethylparaben (and)
	Propylparaben
	(and) Butylparaben (and)
	Isobutylparaben
VI	Fragrance	0.60	0.60	0.60	0.60

Process:

• • 1.—Weigh the components of phase I, add Phase II and heat at 80-85° C.
  • 2.—Weigh the phase III components, homogenize and heat at 80-85° C.
  • 3.—Pour phase I+II over III under constant stirring.
  • 4.—Add Phase IV under stirring until pH=6.5-7.0, when a homogeneous emulsion will form.
  • 5.—Separately, pre-mix Phase V and when the temperature is below 40° C., add it to the emulsion while stirring.
  • 6.—Add the components from Phase VI, one by one, and homogenize. Adjust the pH (6.5-8.5) if necessary.

Sensory Assessment—Purpose

Sensory evaluation is a valuable tool for describing creams, lotions, oils or other compounds from a sensory point of view.

Various parameters are evaluated by a trained panel under usage conditions.

Along with other physical methods (Corneometer, TEWL) it helps to describe the claims of the cosmetic application.

Procedure:

• • 1.—Air-conditioned room 21-24° C.
  • 2.—Trained panel with 11 volunteers.
  • 3.—Assessment is initially carried out 1 minute and 3 minutes after applying the product.
  • 4.—Apply 0.50 g of the test product to the forearm and rub it with the opposite hand, using the 4 fingers.
  • 5.—Spreadability, absorption, oiliness, softness and smoothness are evaluated. We used scales from 1 to 5; where 1=Bad and 5=Excellent.

Formulations B, C and D were submitted to the sensory panel, compared to formula A, where the results are shown in the example in table 4 below:

TABLE 4
EXAMPLE 1
SENSORY PANEL OF FORMULATIONS
B, C and D WITH FORMULA A
	Assessment	Test A	Test B	Test C	Test D
	Spreadability	4	2	3	4
	Absorption	5	3	3	4
	Oiliness	5	3	4	4
	Softness	4	4	4	4
	Smoothness	5	3	4	4

The results show that in this formulation, sensory tests were superior to market products.

EXAMPLE 2

TABLE 5
EXAMPLE 2
OIL-FREE FACE PROTECTOR
Phase	Composition-INCI names	Test 1	Test 2	Test 3	Test 4
I	Diethylamino Hydroxybenzoyl Hexyl	5.00	5.00	5.00	5.00
	Benzoate
I	Ethylhexyl Methoxycinnamate	8.50	8.50	8.50	8.5
I	Cocoyl Glyceryl Solketal	2.00	—	—	—
I	C 12-C15 Alkyl Benzoate	—	2.00	—	—
I	Dibutyl Adipate	—	—	2.00	—
	Dicaprylyl Carbonate	—	—	—	2.00
I	Sodium Acrylates copolymer and Paraffinum	3.00	3.00	3.00	3.00
	Liquid and PPG-1 Trideceth-6
II	Disodium EDTA	0.05	0.05	0.05	0.05
II	Water	100	100	100.	100
III	Methylene Bis Benzotriazolyl
	Tetramethylbutylphenol, aqua,	6.0	6.00	6.00	6.00
	Decylglucoside, Propylene Glycol, Xanthan
	Gum.
III	Aqua	6.00	6.00	6.00	6.00
IV	Phenoxyethanol and Methylparaben and	0.50	0.50	0.50	0.50
	Ethylparaben and Propylparaben and
	Butylparaben and Isobutylparaben
IV	Cyclomethicone	3.00	0.50	0.50	0.50
IV	Aluminum Starch Octenylsuccinate	3.00	3.00	3.00	3.00
IV	fragrance	0.30	0.30	0.30	0.30

Procedure:

• • 1.—Mix Phase I and Phase II and heat to 80-85° C.
  • 2.—Mix them under constant stirring until an emulsion is formed.
  • 3.—Pre-mix Phase III and when the temperature is below 40° ° C., add to the emulsion under constant stirring.
  • 4.—Add the Phase IV components, one by one, and homogenize. Adjust the pH (6.5-8.5) if necessary.

Formulations 2, 3 and 4 were submitted to the sensory panel, compared to formula 1, where the results are shown in the table below. The protocol used was the same as described above, used in the body lotion:

TABLE 6
SENSORY PANEL OF FORMULATIONS
2, 3 and 4 WITH FORMULA 1
	Assessment	Test 1	Test 2	Test 3	Test 4
	Spreadability	5	3	3	4
	Absorption	4	3	4	4
	Oiliness	5	3	4	4
	Softness	4	4	4	4
	Smoothness	5	3	4	4

EXAMPLE 3

TABLE 7
EXAMPLE 3
MAKE UP REMOVER
Phase	Composition-INCI names	Test E	F Test	G Test	H Test
I	Glyceryl Stearate (and)	6.00	6.00	6.00	6.00
	Ceteareth-20(and)
	Ceteareth 12 (and) Cetearyl
	Alcohol (and) Cetyl Palmitate
I	Cetearyl Alcohol	0.50	0.50	0.50	0.50
I	Light Liquid Paraffin	6.00	6.00	6.00	6.00
I	Isopropyl Palmitate	6.0	6.00	6.00	6.00
I	Cocoyl Glyceryl Solketal	3.00	—	—
I	C 12-C15 Alkyl Benzoate	—	3.00	—
I	Dibutyl Adipate	—	—	3.00	—
I	Dicaprylyl Carbonate	—	—	—	3.00
II	Preservative	0.30	0.30	0.30	0.30
II	Water (qs)	100	100	100	100

Procedure:

• • 1.—Mix Phase I and heat to 80-85° C.
  • 2.—Mix Phase II and heat to 80-85° C.
  • 3.—Under stirring, add Phase II over Phase I.
  • 4.—Cool under stirring to 30° C. and unload.

We carried out the performance test, where we evaluated the performance of the emollient in terms of the effectiveness of removing lipstick and makeup.

The Makeup Remover formulations were evaluated according to the protocol below:

• • 1.—Apply the lipstick to the forearm, making a line on it.
  • 2.—Apply the foundation, making a mark on it.
  • 3.—Let it rest for 10 minutes.
  • 4.—Remove it, with a non-woven cloth, moistened with 2 g of the makeup remover to be tested.
  • 5.—Evaluate them, mentioning whether the emollient increased or decreased the removal power. Considering score 1 as decreasing and 2 as increasing.
  • 6—Evaluate the sensorial aspects in terms of softness and smoothness. We used scales from 1 to 5; where 1=Bad and 5=Excellent.

TABLE 8
SENSORY EVALUATION IN SOFTNESS
AND SMOOTHNESS REQUIREMENTS
Assessment	Test E	Test F	Test G	Test H
Makeup Removal Power	2	2	2	2
Softness	5	4	4	4
Smoothness	5	3	4	4

TABLE 9
ROLL ON DEODORANT
Phase	Composition-INCI names	Test I	Test J	Test K	Test L
I.	Glyceryl Stearate (and)	2.1	2.1	2.1
	Ceteareth-20(and)
	Ceteareth 12 (and)				2.1
	Cetearyl Alcohol (and)
	Cetyl Palmitate
	Ceteareth-20	1.9	1.9	1.9	1.9
	Glycerin Mono-Distearate	2.0	2.0	2.0	2.0
	Behenyl Alcohol	1.0	1.0	1.0	1.0
	Ethylhexyl Stearate	1.7	1.7	1.7	1.7
	Cocoyl Glyceryl Solketal	1.7	—	—	—
	C12-C15 Alkyl Benzoate	—	1.7	—	—
	Dibutyl Adipate	—	—	1.7	—
	Dicaprilyl Carbonate	—	—	—	1.7
II.	Edta Dissodico	0.05	0.05	0.05	0.05
	Distilled water (qs)	100.0	100.0	100.0	100.0
III.	Aluminum	40.0	40.0	40.0	40.0
	Sesquihydrochloride
IV.	Fragrance	0.1	0.1	0.1	0.1

Process:

• • 1.—Weigh phase I, heat it to 80° ° C.
  • 2.—Weigh phase II, heat it to 80° C., add phase V over phase II.
  • 3.—Pour phases II+V onto phase I.
  • 4.—Cool the emulsion to 45° C., add phase III and then phase IV.

Protocol:

• • 1.—10 volunteers.
  • 2.—Application to the armpit.

Spreadability, absorption, oiliness, softness and smoothness are evaluated. We used scales from 1 to 5; wherein 1=Bad and 5=Excellent.

Formulations J, K and L were submitted to the sensory panel, compared to formula I, where the results are shown in the table below.

TABLE 10
SENSORY PANEL OF FORMULATIONS
J, K and L WITH FORMULA I.
Assessment	Tested	Test J	Test K	Test L
Spreadability	5	3	3	4
Absorption	5	3	4	4
Oiliness	5	3	4	4
Softness	5	4	4	4
Smoothness	5	4	4	4

In all these formulations, Cocoil Glyceryl Solketal demonstrated its solubilizing and/or emollient characteristics in these cosmetic applications.

Claims

1. A synthetic molecule of solketal esters from palm kit oil and glycerin for cosmetic and agricultural formulations wherein mono glyceryl solketal ester is obtained from palm kernel oil, coconut oil, macauba oil and glycerin as solubilizer in the form of the cocoyl solketal ester, more particularly the solketal monoester prepared from oils and/or fatty acids of coconut, babassu, palm kernel, represented by the chemical structure

2. The synthetic molecule of solketal esters from palm kit oil and glycerin for cosmetic and agricultural formulations, according to claim 1, wherein the esters are prepared from esterification or transesterification, and the acetals can be prepared in advance or in situ, that is, with the formation reactions of acetals, esters formed concomitantly.

3. The synthetic molecule of solketal esters from palm kit oil and glycerin for cosmetic and agricultural formulations, according to claim 1, wherein glyceryl solketals are prepared from glycerin of various degrees of purity, more particularly purified glycerins with a above 90% purity.

4. The synthetic molecule of solketal esters from palm kit oil and glycerin for cosmetic and agricultural formulations, according to claim 1, wherein it is used in protective filters against solar radiation, emollients, as aqueous or oily spreading agents.

5. The synthetic molecule of solketal esters from palm kit oil and glycerin for cosmetic and agricultural formulations, according to claim 1, wherein it is used in cosmetic formulations for makeup removal.

6. The synthetic molecule of solketal esters from palm kit oil and glycerin for cosmetic and agricultural formulations, according to claim 1, wherein it is used in antiperspirant deodorant formulations of the “roll on” or spray type.

7. The synthetic molecule of solketal esters from palm kit oil and glycerin for cosmetic and agricultural formulations, according to claim 1, wherein it is used for agricultural formulations as a solubilizer of herbicide, insecticide, fungicide and acaricide molecules.